Trabajando con los precios en la biblioteca DoEasy (Parte 62): Actualización de las series de tick en tiempo real, preparando para trabajar con la Profundidad del mercado

Contenido

• Concepto
• Mejorando las clases de la biblioteca
• Actualizando las series de tick
• Mejorando la clase del símbolo para trabajar con la Profundidad del mercado
• Prueba
• ¿Qué es lo próximo?
  

Concepto

Bien, hemos creado la colección de datos de tick para todos los símbolos utilizados en el programa. La biblioteca es capaz de obtener la cantidad requerida de datos de tick para cada símbolo utilizado en el programa, y los almacena en una colección de datos de tick. La colección de datos de tick permite encontrar cualquier objeto de tick requerido y obtener sus datos. Nosotros podemos filtrar y ordenar las listas para realizar estudios estadísticos, pero los ticks nuevos no se colocan en la base de los ticks cuando ellos llegan para cada uno de los símbolos. Hoy vamos a crear esta posibilidad.

Además, cada nuevo tick va a aumentar la cantidad de objetos almacenados en la colección. Para limitar esta cantidad, y por consiguiente, el volumen de la memoria utilizada, vamos a introducir una constante donde se puede definir el número máximo posible de los ticks que se guarda en la base de la biblioteca para un símbolo. Eso va a ser un seguro contra la falta de la memoria. Si en el programa se utilizan muchos instrumentos y si se ha acumulado una gran cantidad de ticks en la base, la biblioteca eliminará automáticamente la cantidad necesaria de los ticks más antiguos. De esta manera, vamos a tener una cantidad establecida de los ticks para cada instrumento. Por defecto, serán 200 000. Esta cantidad debe ser suficiente para realizar estudios estadísticos aproximadamente durante dos últimos días. En cualquier caso, si es necesario, Ud. siempre podrá modificar el número máximo de los ticks almacenados en la colección para un instrumento.

Además, hoy empezaremos a preparar la interacción con la Profundidad del mercado (en inglés Depth of Market, o DOM). Crearemos la posibilidad de suscribirnos a la transmisión del DOM en la clase del objeto de símbolo. En los siguientes artículos, empezaremos a crear la funcionalidad para trabajar con el DOM.

Mejorando las clases de la biblioteca

Vamos a comenzar como siempre, añadiendo los nuevos mensajes de texto de la biblioteca.
Añadimos los índices de nuevos mensajes al archivo \MQL5\Include\DoEasy\Data.mqh:

   MSG_SYM_EVENT_SYMBOL_ADD,                          // Added symbol to Market Watch window
   MSG_SYM_EVENT_SYMBOL_DEL,                          // Symbol removed from Market Watch window
   MSG_SYM_EVENT_SYMBOL_SORT,                         // Changed location of symbols in Market Watch window
   MSG_SYM_SYMBOLS_MODE_CURRENT,                      // Work with current symbol only
   MSG_SYM_SYMBOLS_MODE_DEFINES,                      // Work with predefined symbol list
   MSG_SYM_SYMBOLS_MODE_MARKET_WATCH,                 // Work with Market Watch window symbols
   MSG_SYM_SYMBOLS_MODE_ALL,                          // Work with full list of all available symbols
   MSG_SYM_SYMBOLS_BOOK_ADD,                          // Subscribed to Depth of Market 
   MSG_SYM_SYMBOLS_BOOK_DEL,                          // Unsubscribed from Depth of Market 
   MSG_SYM_SYMBOLS_MODE_BOOK,                         // Subscription to Depth of Market
   
//--- CAccount

y añadimos los mensajes de texto correspondientes a los índices nuevamente añadidos:

   {"В окно \"Обзор рынка\" добавлен символ","Added symbol to \"Market Watch\" window"},
   {"Из окна \"Обзор рынка\" удалён символ","Removed from \"Market Watch\" window"},
   {"Изменено расположение символов в окне \"Обзор рынка\"","Changed arrangement of symbols in \"Market Watch\" window"},
   {"Работа только с текущим символом","Work only with the current symbol"},
   {"Работа с предопределённым списком символов","Work with predefined list of symbols"},
   {"Работа с символами из окна \"Обзор рынка\"","Working with symbols from \"Market Watch\" window"},
   {"Работа с полным списком всех доступных символов","Work with full list of all available symbols"},
   {"Осуществлена подписка на стакан цен ","Subscribed to Depth of Market"},
   {"Осуществлена отписка от стакан цен ","Unsubscribed from Depth of Market"},
   {"Подписка на стакан цен","Subscription to Depth of Market"},
   
//--- CAccount

Como hoy vamos a dedicarnos a la actualización de la colección de datos de tick en tiempo real, aclararemos cómo será el proceso: cuando nuevo tick llega para un símbolo, tenemos que añadir este tick a la estructura MqlTick, crear un nuevo objeto de tick a su base y añadirlo a la lista de la serie de tick que se almacena en la colección junto con las listas de otros símbolos. Pero no podemos obtener los ticks para otros símbolos en el manejador OnTick() del programa, ya que este manejador se activa con la llegada de un nuevo tick en el símbolo actual. Por eso, para obtener los ticks nuevos para otros símbolos que se utilizan, tenemos que controlarlos en el temporizador de la biblioteca usando el objeto de la clase «Nuevo tick» creado anteriormente. Para eso necesitamos tener otro temporizador en la biblioteca en el que los ticks para todos los instrumentos salvo el actual van a ser monitoreados para la actualización de las listas de datos de tick de estos instrumentos.

En el archivo \MQL5\Include\DoEasy\Defines.mqh vamos a añadir los parámetros del temporizador de la colección de datos de tick y una constante para indicar el número máximo posible de objetos de tick para un símbolo:

//--- Parameters of the timer of indicator data timeseries collection
#define COLLECTION_IND_TS_PAUSE        (64)                       // Pause of the timer of indicator data timeseries collection in milliseconds
#define COLLECTION_IND_TS_COUNTER_STEP (16)                       // Increment of indicator data timeseries timer counter
#define COLLECTION_IND_TS_COUNTER_ID   (7)                        // ID of indicator data timeseries timer counter
//--- Parameters of the tick series collection timer
#define COLLECTION_TICKS_PAUSE         (64)                       // Tick series collection timer pause in milliseconds
#define COLLECTION_TICKS_COUNTER_STEP  (16)                       // Tick series timer counter increment step
#define COLLECTION_TICKS_COUNTER_ID    (8)                        // Tick series timer counter ID
//--- Collection list IDs
#define COLLECTION_HISTORY_ID          (0x777A)                   // Historical collection list ID
#define COLLECTION_MARKET_ID           (0x777B)                   // Market collection list ID
#define COLLECTION_EVENTS_ID           (0x777C)                   // Event collection list ID
#define COLLECTION_ACCOUNT_ID          (0x777D)                   // Account collection list ID
#define COLLECTION_SYMBOLS_ID          (0x777E)                   // Symbol collection list ID
#define COLLECTION_SERIES_ID           (0x777F)                   // Timeseries collection list ID
#define COLLECTION_BUFFERS_ID          (0x7780)                   // Indicator buffer collection list ID
#define COLLECTION_INDICATORS_ID       (0x7781)                   // Indicator collection list ID
#define COLLECTION_INDICATORS_DATA_ID  (0x7782)                   // Indicator data collection list ID
#define COLLECTION_TICKSERIES_ID       (0x7783)                   // Tick series collection list ID
//--- Data parameters for file operations
#define DIRECTORY                      ("DoEasy\\")               // Library directory for storing object folders
#define RESOURCE_DIR                   ("DoEasy\\Resource\\")     // Library directory for storing resource folders
//--- Symbol parameters
#define CLR_DEFAULT                    (0xFF000000)               // Default symbol background color in the navigator
#ifdef __MQL5__
   #define SYMBOLS_COMMON_TOTAL        (TerminalInfoInteger(TERMINAL_BUILD)<2430 ? 1000 : 5000)   // Total number of MQL5 working symbols
#else 
   #define SYMBOLS_COMMON_TOTAL        (1000)                     // Total number of MQL4 working symbols
#endif 
//--- Pending request type IDs
#define PENDING_REQUEST_ID_TYPE_ERR    (1)                        // Type of a pending request created based on the server return code
#define PENDING_REQUEST_ID_TYPE_REQ    (2)                        // Type of a pending request created by request
//--- Timeseries parameters
#define SERIES_DEFAULT_BARS_COUNT      (1000)                     // Required default amount of timeseries data
#define PAUSE_FOR_SYNC_ATTEMPTS        (16)                       // Amount of pause milliseconds between synchronization attempts
#define ATTEMPTS_FOR_SYNC              (5)                        // Number of attempts to receive synchronization with the server
//--- Tick series parameters
#define TICKSERIES_DEFAULT_DAYS_COUNT  (1)                        // Required number of days for tick data in default series
#define TICKSERIES_MAX_DATA_TOTAL      (200000)                   // Maximum number of stored tick data of a single symbol
//+------------------------------------------------------------------+

Para poder comprender si estamos suscritos a la transmisión del DOM por el símbolo, tenemos que completar las propiedades del símbolo con el parámetro que indique en el estado de la suscripción. Para eso, vamos a añadir un parámetro nuevo a las propiedades de tipo entero del símbolo y aumentaremos así su número de 36 a 37.

//+------------------------------------------------------------------+
//| Symbol integer properties                                        |
//+------------------------------------------------------------------+
enum ENUM_SYMBOL_PROP_INTEGER
  {
   SYMBOL_PROP_STATUS = 0,                                  // Symbol status
   SYMBOL_PROP_INDEX_MW,                                    // Symbol index in the Market Watch window
   SYMBOL_PROP_CUSTOM,                                      // Custom symbol flag
   SYMBOL_PROP_CHART_MODE,                                  // The price type used for generating bars – Bid or Last (from the ENUM_SYMBOL_CHART_MODE enumeration)
   SYMBOL_PROP_EXIST,                                       // Flag indicating that the symbol under this name exists
   SYMBOL_PROP_SELECT,                                      // The indication that the symbol is selected in Market Watch
   SYMBOL_PROP_VISIBLE,                                     // The indication that the symbol is displayed in Market Watch
   SYMBOL_PROP_SESSION_DEALS,                               // The number of deals in the current session 
   SYMBOL_PROP_SESSION_BUY_ORDERS,                          // The total number of Buy orders at the moment
   SYMBOL_PROP_SESSION_SELL_ORDERS,                         // The total number of Sell orders at the moment
   SYMBOL_PROP_VOLUME,                                      // Last deal volume
   SYMBOL_PROP_VOLUMEHIGH,                                  // Maximum volume within a day
   SYMBOL_PROP_VOLUMELOW,                                   // Minimum volume within a day
   SYMBOL_PROP_TIME,                                        // Latest quote time
   SYMBOL_PROP_DIGITS,                                      // Number of decimal places
   SYMBOL_PROP_DIGITS_LOTS,                                 // Number of decimal places for a lot
   SYMBOL_PROP_SPREAD,                                      // Spread in points
   SYMBOL_PROP_SPREAD_FLOAT,                                // Floating spread flag
   SYMBOL_PROP_TICKS_BOOKDEPTH,                             // Maximum number of orders displayed in the Depth of Market
   SYMBOL_PROP_BOOKDEPTH_STATE,                             // Flag of subscription to DOM
   SYMBOL_PROP_TRADE_CALC_MODE,                             // Contract price calculation method (from the ENUM_SYMBOL_CALC_MODE enumeration)
   SYMBOL_PROP_TRADE_MODE,                                  // Order execution type (from the ENUM_SYMBOL_TRADE_MODE enumeration)
   SYMBOL_PROP_START_TIME,                                  // Symbol trading start date (usually used for futures)
   SYMBOL_PROP_EXPIRATION_TIME,                             // Symbol trading end date (usually used for futures)
   SYMBOL_PROP_TRADE_STOPS_LEVEL,                           // Minimum distance in points from the current close price for setting Stop orders
   SYMBOL_PROP_TRADE_FREEZE_LEVEL,                          // Freeze distance for trading operations (in points)
   SYMBOL_PROP_TRADE_EXEMODE,                               // Deal execution mode (from the ENUM_SYMBOL_TRADE_EXECUTION enumeration)
   SYMBOL_PROP_SWAP_MODE,                                   // Swap calculation model (from the ENUM_SYMBOL_SWAP_MODE enumeration)
   SYMBOL_PROP_SWAP_ROLLOVER3DAYS,                          // Triple-day swap (from the ENUM_DAY_OF_WEEK enumeration)
   SYMBOL_PROP_MARGIN_HEDGED_USE_LEG,                       // Calculating hedging margin using the larger leg (Buy or Sell)
   SYMBOL_PROP_EXPIRATION_MODE,                             // Flags of allowed order expiration modes
   SYMBOL_PROP_FILLING_MODE,                                // Flags of allowed order filling modes
   SYMBOL_PROP_ORDER_MODE,                                  // Flags of allowed order types
   SYMBOL_PROP_ORDER_GTC_MODE,                              // Expiration of Stop Loss and Take Profit orders if SYMBOL_EXPIRATION_MODE=SYMBOL_EXPIRATION_GTC (from the ENUM_SYMBOL_ORDER_GTC_MODE enumeration)
   SYMBOL_PROP_OPTION_MODE,                                 // Option type (from the ENUM_SYMBOL_OPTION_MODE enumeration)
   SYMBOL_PROP_OPTION_RIGHT,                                // Option right (Call/Put) (from the ENUM_SYMBOL_OPTION_RIGHT enumeration)
   //--- skip the property
   SYMBOL_PROP_BACKGROUND_COLOR                             // The color of the background used for the symbol in Market Watch
  }; 
#define SYMBOL_PROP_INTEGER_TOTAL    (37)                   // Total number of integer properties
#define SYMBOL_PROP_INTEGER_SKIP     (1)                    // Number of symbol integer properties not used in sorting
//+------------------------------------------------------------------+

Vamos a añadir la ordenación según una nueva propiedad entera a las enumeraciones de posibles criterios de ordenación de los objetos de símbolos:

//+------------------------------------------------------------------+
//| Possible symbol sorting criteria                                 |
//+------------------------------------------------------------------+
#define FIRST_SYM_DBL_PROP          (SYMBOL_PROP_INTEGER_TOTAL-SYMBOL_PROP_INTEGER_SKIP)
#define FIRST_SYM_STR_PROP          (SYMBOL_PROP_INTEGER_TOTAL-SYMBOL_PROP_INTEGER_SKIP+SYMBOL_PROP_DOUBLE_TOTAL-SYMBOL_PROP_DOUBLE_SKIP)
enum ENUM_SORT_SYMBOLS_MODE
  {
//--- Sort by integer properties
   SORT_BY_SYMBOL_STATUS = 0,                               // Sort by symbol status
   SORT_BY_SYMBOL_INDEX_MW,                                 // Sort by index in the Market Watch window
   SORT_BY_SYMBOL_CUSTOM,                                   // Sort by custom symbol property
   SORT_BY_SYMBOL_CHART_MODE,                               // Sort by price type for constructing bars – Bid or Last (from the ENUM_SYMBOL_CHART_MODE enumeration)
   SORT_BY_SYMBOL_EXIST,                                    // Sort by the flag that a symbol with such a name exists
   SORT_BY_SYMBOL_SELECT,                                   // Sort by the flag indicating that a symbol is selected in Market Watch
   SORT_BY_SYMBOL_VISIBLE,                                  // Sort by the flag indicating that a selected symbol is displayed in Market Watch
   SORT_BY_SYMBOL_SESSION_DEALS,                            // Sort by the number of deals in the current session 
   SORT_BY_SYMBOL_SESSION_BUY_ORDERS,                       // Sort by the total number of current buy orders
   SORT_BY_SYMBOL_SESSION_SELL_ORDERS,                      // Sort by the total number of current sell orders
   SORT_BY_SYMBOL_VOLUME,                                   // Sort by last deal volume
   SORT_BY_SYMBOL_VOLUMEHIGH,                               // Sort by maximum volume for a day
   SORT_BY_SYMBOL_VOLUMELOW,                                // Sort by minimum volume for a day
   SORT_BY_SYMBOL_TIME,                                     // Sort by the last quote time
   SORT_BY_SYMBOL_DIGITS,                                   // Sort by a number of decimal places
   SORT_BY_SYMBOL_DIGITS_LOT,                               // Sort by a number of decimal places in a lot
   SORT_BY_SYMBOL_SPREAD,                                   // Sort by spread in points
   SORT_BY_SYMBOL_SPREAD_FLOAT,                             // Sort by floating spread
   SORT_BY_SYMBOL_TICKS_BOOKDEPTH,                          // Sort by a maximum number of requests displayed in the market depth
   SORT_BY_SYMBOL_BOOKDEPTH_STATE,                          // Sort by the DOM subscription flag
   SORT_BY_SYMBOL_TRADE_CALC_MODE,                          // Sort by contract price calculation method (from the ENUM_SYMBOL_CALC_MODE enumeration)
   SORT_BY_SYMBOL_TRADE_MODE,                               // Sort by order execution type (from the ENUM_SYMBOL_TRADE_MODE enumeration)
   SORT_BY_SYMBOL_START_TIME,                               // Sort by an instrument trading start date (usually used for futures)
   SORT_BY_SYMBOL_EXPIRATION_TIME,                          // Sort by an instrument trading end date (usually used for futures)
   SORT_BY_SYMBOL_TRADE_STOPS_LEVEL,                        // Sort by the minimum indent from the current close price (in points) for setting Stop orders
   SORT_BY_SYMBOL_TRADE_FREEZE_LEVEL,                       // Sort by trade operation freeze distance (in points)
   SORT_BY_SYMBOL_TRADE_EXEMODE,                            // Sort by trade execution mode (from the ENUM_SYMBOL_TRADE_EXECUTION enumeration)
   SORT_BY_SYMBOL_SWAP_MODE,                                // Sort by swap calculation model (from the ENUM_SYMBOL_SWAP_MODE enumeration)
   SORT_BY_SYMBOL_SWAP_ROLLOVER3DAYS,                       // Sort by week day for accruing a triple swap (from the ENUM_DAY_OF_WEEK enumeration)
   SORT_BY_SYMBOL_MARGIN_HEDGED_USE_LEG,                    // Sort by the calculation mode of a hedged margin using the larger leg (Buy or Sell)
   SORT_BY_SYMBOL_EXPIRATION_MODE,                          // Sort by flags of allowed order expiration modes
   SORT_BY_SYMBOL_FILLING_MODE,                             // Sort by flags of allowed order filling modes
   SORT_BY_SYMBOL_ORDER_MODE,                               // Sort by flags of allowed order types
   SORT_BY_SYMBOL_ORDER_GTC_MODE,                           // Sort by StopLoss and TakeProfit orders lifetime
   SORT_BY_SYMBOL_OPTION_MODE,                              // Sort by option type (from the ENUM_SYMBOL_OPTION_MODE enumeration)
   SORT_BY_SYMBOL_OPTION_RIGHT,                             // Sort by option right (Call/Put) (from the ENUM_SYMBOL_OPTION_RIGHT enumeration)
//--- Sort by real properties

Actualizando las series de tick

Puesto que los ticks pueden llegar simultáneamente en un paquete, no podremos añadirlos uno por uno a la lista de la serie de tick. Para guardar todos los ticks que han llegado en un paquete, es necesario controlar la hora en milisegundos del último tick obtenido y copiar los ticks a partir de esta hora hasta el final de datos históricos. Después de copiar todos los nuevos ticks que han llegado (puede haber un tick o varios en un paquete), tenemos que guardar la hora del último tick. Lo necesitamos para empezar a copiar los ticks cuando OnTick() se active otra vez. Los ticks van a copiarse a partir de esta hora + 1 milisegundo (para no copiar el último tick anterior otra vez) hasta el final de datos históricos (hasta la hora actual). De esta manera, cada vez cuando se active OnTick(), podremos obtener todos los datos necesarios que aparecen con la llegada de un nuevo tick, y después del copiado, recordar la hora nueva del último tick para el copiado posterior.

A la hora de crear el método para actualizar la serie de tick, ha resultado que la creación de un nuevo objeto de datos de tick y su adición a la lista de la serie de tick son idénticas a la creación de un nuevo objeto de datos de tick y su adición a la lista en el método de la creación de la serie de tick que ya ha sido creado. Por tanto, este bloque del código ha sido trasladado al método nuevo que devuelve el puntero al objeto nuevamente creado y añadido a la lista, o NULL. Este nuevo método de la creación de la lista modificado y el nuevo método para actualizar la lista serán considerados más abajo.

En la sección privada de la clase del archivo \MQL5\Include\DoEasy\Objects\Ticks\TickSeries.mqh, vamos a declarar una variable de miembro de la clase para guardar la hora en milisegundos del último tick y el método para crear un nuevo objeto de tick y añadirlo a la lista de serie de tick:

//+------------------------------------------------------------------+
//| "Tick data series" class                                         |
//+------------------------------------------------------------------+
class CTickSeries : public CBaseObj
  {
private:
   string            m_symbol;                                          // Symbol
   ulong             m_last_time;                                       // Last tick time
   uint              m_amount;                                          // Amount of applied tick series data
   uint              m_required;                                        // Required number of days for tick series data
   CArrayObj         m_list_ticks;                                      // List of tick data
   CNewTickObj       m_new_tick_obj;                                    // "New tick" object
//--- Create a new tick data object
   CDataTick        *CreateNewTickObj(const MqlTick &tick);

public:

En la clase pública de la clase, declaramos el método que devuelve el puntero al último objeto de datos de tick en la lista:

//--- Return the object of tick data by (1) index in the list, (2) time,
//--- (3) time in milliseconds, (4) the last one in the list and (5) the list size
   CDataTick        *GetTickByListIndex(const uint index);
   CDataTick        *GetTick(const datetime time); 
   CDataTick        *GetTick(const ulong time_msc); 
   CDataTick        *GetLastTick(void); 
   int               DataTotal(void)                              const { return this.m_list_ticks.Total();       }

//--- The comparison method for searching identical tick series objects by a symbol

Ya que necesitaremos usar el objeto «Nuevo tick», para su correcto funcionamiento, tendremos que especificar con qué símbolo va a trabajar.
Lo haremos en el constructor de clase:

//+------------------------------------------------------------------+
//| Parametric constructor                                           |
//+------------------------------------------------------------------+
CTickSeries::CTickSeries(const string symbol,const uint required=0) : m_symbol(symbol),m_last_time(0)
  {
   this.m_list_ticks.Clear();
   this.m_list_ticks.Sort(SORT_BY_TICK_TIME_MSC);
   this.SetRequiredUsedDays(required);
   this.m_new_tick_obj.SetSymbol(this.m_symbol);
   this.m_new_tick_obj.Refresh();
  }
//+------------------------------------------------------------------+

Inmediatamente después de establecer el símbolo, actualizaremos una vez los datos en el objeto «Nuevo tick» para recordar la hora del último tick en este objeto.

Método para crear un nuevo objeto de datos de tick y ubicarlo en la lista:

//+------------------------------------------------------------------+
//| Create a new tick data object                                    |
//+------------------------------------------------------------------+
CDataTick *CTickSeries::CreateNewTickObj(const MqlTick &tick)
  {
   //--- create a new object of tick data out of the MqlTick structure passed to the method
   int err=ERR_SUCCESS;
   ::ResetLastError();
   //--- If failed to create an object, inform of that and return NULL
   CDataTick* tick_obj=new CDataTick(this.m_symbol,tick);
   if(tick_obj==NULL)
     {
      ::Print
        (
         DFUN,CMessage::Text(MSG_TICKSERIES_FAILED_CREATE_TICK_DATA_OBJ)," ",this.Header()," ",::TimeMSCtoString(tick.time_msc),". ",
         CMessage::Text(MSG_LIB_SYS_ERROR),": ",CMessage::Text(::GetLastError())
        );
      return NULL;
     }
   //--- If failed to add a new tick data object to the list,
   //--- display the appropriate message with the error description in the journal,
   //--- remove the newly created object and return NULL
   this.m_list_ticks.Sort();
   if(!this.m_list_ticks.InsertSort(tick_obj))
     {
      err=::GetLastError();
      ::Print(DFUN,CMessage::Text(MSG_TICKSERIES_FAILED_ADD_TO_LIST)," ",tick_obj.Header()," ",
                   CMessage::Text(MSG_LIB_SYS_ERROR),": ",CMessage::Text(err),CMessage::Retcode(err));
      delete tick_obj;
      return NULL;
     }
   //--- Return the pointer to the tick data object that was created and added to the list
   return tick_obj;
  }
//+------------------------------------------------------------------+

La lógica del método se detalla en los comentarios. Precisamente este bloque fue trasladado a este nuevo método desde el método para crear la lista de la serie de tick que habíamos creado en el artículo anterior. Ahora, transmitimos a este método la estructura de tick a base de cuyos datos es necesario crear un objeto nuevo de datos de tick. Después de terminar su creación y adición a la lista, se devuelve el puntero a este objeto, o NULL si no se ha podido crear o añadir el objeto a la lista.

Método para crear la lista de serie de datos de tick

//+------------------------------------------------------------------+
//| Create the series list of tick data                              |
//+------------------------------------------------------------------+
int CTickSeries::Create(const uint required=0)
  {
//--- If the tick series is not used, inform of that and exit
   if(!this.m_available)
     {
      ::Print(DFUN,this.m_symbol,": ",CMessage::Text(MSG_TICKSERIES_TEXT_IS_NOT_USE));
      return false;
     }
//--- Declare the ticks[] array we are to receive historical data to,
//--- clear the list of tick data objects and set the flag of sorting by time in milliseconds
   MqlTick ticks_array[];
   this.m_list_ticks.Clear();
   this.m_list_ticks.Sort(SORT_BY_TICK_TIME_MSC);
   this.m_last_time=0;
   ::ResetLastError();
   int err=ERR_SUCCESS;
//--- Calculate the day start time in milliseconds the ticks should be copied from
   MqlDateTime date_str={0};
   datetime date=::iTime(m_symbol,PERIOD_D1,this.m_required);
   ::TimeToStruct(date,date_str);
   date_str.hour=date_str.min=date_str.sec=0;
   date=::StructToTime(date_str);
   long date_from=(long)date*1000;
   if(date_from<1) date_from=1;
//--- Get historical data of the MqlTick structure to the tick[] array
//--- from the calculated date to the current time and save the obtained number in m_amount.
//--- If failed to get data, display the appropriate message and return zero
   this.m_amount=::CopyTicksRange(m_symbol,ticks_array,COPY_TICKS_ALL,date_from);
   if(this.m_amount<1)
     {
      err=::GetLastError();
      ::Print(DFUN,CMessage::Text(MSG_TICKSERIES_ERR_GET_TICK_DATA),": ",CMessage::Text(err),CMessage::Retcode(err));
      return 0;
     }
//--- Historical data is received in the rates[] array
//--- In the ticks[] array loop
   for(int i=0; i<(int)this.m_amount; i++)
     {
      //--- Create the tick object and add it to the list
      CDataTick *tick_obj=this.CreateNewTickObj(ticks_array[i]);
      if(tick_obj==NULL)
         continue;
      //--- If the tick time exceeds the previous one, write the new tick time to m_last_time as the starting one
      //--- to copy the newly arrived ticks in the tick series update method
      if(this.m_last_time<(ulong)tick_obj.TimeMSC())
         this.m_last_time=tick_obj.TimeMSC();
     }
//--- Return the size of the created tick object list
   return this.m_list_ticks.Total();
  }
//+------------------------------------------------------------------+

El método fue escrito en el artículo dedicado a la creación de las series de tick. Aquí, lo hemos modificado de tal manera que ahora el nuevo objeto de datos de tick se crea y se añade usando el nuevo método considerado más arriba. Después de añadir con éxito el objeto a la lista, guardamos la hora del último tick para su uso posterior en el método de actualización de la serie de tick.

Métodos para actualizar la serie de tick:

//+------------------------------------------------------------------+
//| Update the tick series list                                      |
//+------------------------------------------------------------------+
void CTickSeries::Refresh(void)
  {
   MqlTick ticks_array[];
   if(IsNewTick())
     {
      //--- Copy ticks from m_last_time time+1 ms to the end of history
      int err=ERR_SUCCESS;
      int total=::CopyTicksRange(this.Symbol(),ticks_array,COPY_TICKS_ALL,this.m_last_time+1,0);
      //--- If the ticks have been copied, create new tick data objects and add them to the list in the loop by their number
      if(total>0)
        {
         for(int i=0;i<total;i++)
           {
            //--- Create the tick object and add it to the list
            CDataTick *tick_obj=this.CreateNewTickObj(ticks_array[i]);
            if(tick_obj==NULL)
               break;
            //--- Write the last tick time for subsequent copying of newly arrived ticks
            long end_time=ticks_array[::ArraySize(ticks_array)-1].time_msc;
            if(this.Symbol()=="AUDUSD")
               Comment(DFUN,this.Symbol(),", copied=",total,", m_last_time=",TimeMSCtoString(m_last_time),", end_time=",TimeMSCtoString(end_time),", total=",DataTotal());
            this.m_last_time=end_time;
           }
         //--- If the number of ticks in the list exceeds the default maximum number,
         //--- remove the calculated number of tick objects from the end of the list
         if(this.DataTotal()>TICKSERIES_MAX_DATA_TOTAL)
           {
            int total_del=m_list_ticks.Total()-TICKSERIES_MAX_DATA_TOTAL;
            for(int j=0;j<total_del;j++)
               this.m_list_ticks.Delete(j);
           }
        }
     }
  }
//+------------------------------------------------------------------+

Aquí, todo es bastante simple. Tenemos la hora del último tick registrada durante la activación anterior de OnTick(), que se guarda en la variable m_last_time. Ahora, para empezar a copiar nuevos ticks, tenemos que agregar un milisegundo a esta hora, porque la función CopyTicksRange() copia a partir de la hora especificada, inclusive esta hora. Precisamente por esta razón, para evitar incluir en la lista de serie el objeto de tick ya copiado antes a los ticks copiados durante la nueva activación de OnTick(), empezamos a copiar a partir de la hora con diferencia en un milisegundo en vez de copiar a partir de la hora registrada en el tick anterior. Si después de copiar y añadir nuevos ticks a la lista su numero total supera el valor mínimo permitido que ha sido establecido para ellos, calculamos la cantidad de objetos sobrantes en la lista y los eliminamos de ahí (se trata de los objetos de tick más antiguos).

Al método se le han sido añadidos a propósito las líneas del código que visualizan los datos según el número de ticks copiados, la hora pasada y actual y el número total de datos de tick en la lista de la serie de tick con el fin de verificar la corrección de su copiado, y sólo para el símbolo AUDUSD.
Quitaremos estas cadenas en los artículos siguientes. Mientras tanto, estas cadenas podrán mostrarnos que los ticks para un símbolo «no nativo» se copian en el temporizador de la biblioteca y los objetos de datos de tick se introducen en la lista de serie de tick.

Método para devolver el último objeto de datos de tick de la lista:

//+------------------------------------------------------------------+
//| Return the most recent tick data object from the list            |
//+------------------------------------------------------------------+
CDataTick *CTickSeries::GetLastTick(void)
  {
   return this.m_list_ticks.At(this.m_list_ticks.Total()-1);
  }
//+------------------------------------------------------------------+

El método simplemente retorna un puntero al objeto almacenado en la lista en último lugar.

Ahora, mejoraremos un poco la clase de colección de las series de tick en el archivo \MQL5\Include\DoEasy\Collections\TickSeriesCollection.mqh.

Como tendremos que actualizar las series de tick del símbolo actual por separado de los demás (la serie para el símbolo actual va a actualizarse en el manejador OnTick() de la biblioteca, mientras que los demás datos de tick de otros símbolos se actualizarán en el temporizador de la biblioteca), entonces, vamos a crear un método para actualizar todas las series de tick de la colección excepto la serie del símbolo actual. Declaramos el método en la sección pública de la clase:

//--- Update (1) a tick series of a specified symbol, (2) all symbols and (3) all symbols except the current one
   void                    Refresh(const string symbol);
   void                    Refresh(void);
   void                    RefreshExpectCurrent(void);

//--- Display (1) the complete and (2) short collection description in the journal

y escribimos su implementación fuera del cuerpo de la clase:

//+------------------------------------------------------------------+
//| Update tick series of all symbols except the current one         |
//+------------------------------------------------------------------+
void CTickSeriesCollection::RefreshExpectCurrent(void)
  {
   for(int i=0;i<this.m_list.Total();i++)
     {
      CTickSeries *tickseries=this.m_list.At(i);
      if(tickseries==NULL || tickseries.Symbol()==::Symbol())
         continue;
      tickseries.Refresh();
     }
  }
//+------------------------------------------------------------------+

Repasando en el ciclo el número total de las series de tick en la colección, obtenemos el siguiente objeto de la serie de tick de la lista. Si su símbolo coincide con el símbolo del gráfico en el que ha sido iniciado el programa, omitimos esta serie. Actualizamos todas las demás series de tick.

Al objeto principal de la biblioteca CEngine en el archivo \MQL5\Include\DoEasy\Engine.mqh le añadimos tres métodos: para actualizar la serie de tick del símbolo especificado , para actualizar todas las series de tick, y para actualizar todas las series de tick excepto la serie del símbolo actual:

//--- Return (1) the tick series collection, (2) the list of tick series from the tick series collection
   CTickSeriesCollection *GetTickSeriesCollection(void)                                { return &this.m_tick_series;                         }
   CArrayObj           *GetListTickSeries(void)                                        { return this.m_tick_series.GetList();                }

//--- Update (1) a tick series of a specified symbol, (2) all symbols and (3) all symbols except the current one
   void                 TickSeriesRefresh(const string symbol)                         { this.m_tick_series.Refresh(symbol);                 }
   void                 TickSeriesRefreshAll(void)                                     { this.m_tick_series.Refresh();                       }
   void                 TickSeriesRefreshAllExceptCurrent(void)                        { this.m_tick_series.RefreshExpectCurrent();          }

//--- Return (1) the buffer collection and (2) the buffer list from the collection 

Los métodos simplemente llaman a los métodos homónimos de la clase de colección de las series de tick.

En el constructor de la clase, añadimos la creación del temporizador de la colección de datos de tick:

//+------------------------------------------------------------------+
//| CEngine constructor                                              |
//+------------------------------------------------------------------+
CEngine::CEngine() : m_first_start(true),
                     m_last_trade_event(TRADE_EVENT_NO_EVENT),
                     m_last_account_event(WRONG_VALUE),
                     m_last_symbol_event(WRONG_VALUE),
                     m_global_error(ERR_SUCCESS)
  {
   this.m_is_hedge=#ifdef __MQL4__ true #else bool(::AccountInfoInteger(ACCOUNT_MARGIN_MODE)==ACCOUNT_MARGIN_MODE_RETAIL_HEDGING) #endif;
   this.m_is_tester=::MQLInfoInteger(MQL_TESTER);
   this.m_program=(ENUM_PROGRAM_TYPE)::MQLInfoInteger(MQL_PROGRAM_TYPE);
   this.m_name=::MQLInfoString(MQL_PROGRAM_NAME);
   
   this.m_list_counters.Sort();
   this.m_list_counters.Clear();
   this.CreateCounter(COLLECTION_ORD_COUNTER_ID,COLLECTION_ORD_COUNTER_STEP,COLLECTION_ORD_PAUSE);
   this.CreateCounter(COLLECTION_ACC_COUNTER_ID,COLLECTION_ACC_COUNTER_STEP,COLLECTION_ACC_PAUSE);
   this.CreateCounter(COLLECTION_SYM_COUNTER_ID1,COLLECTION_SYM_COUNTER_STEP1,COLLECTION_SYM_PAUSE1);
   this.CreateCounter(COLLECTION_SYM_COUNTER_ID2,COLLECTION_SYM_COUNTER_STEP2,COLLECTION_SYM_PAUSE2);
   this.CreateCounter(COLLECTION_REQ_COUNTER_ID,COLLECTION_REQ_COUNTER_STEP,COLLECTION_REQ_PAUSE);
   this.CreateCounter(COLLECTION_TS_COUNTER_ID,COLLECTION_TS_COUNTER_STEP,COLLECTION_TS_PAUSE);
   this.CreateCounter(COLLECTION_IND_TS_COUNTER_ID,COLLECTION_IND_TS_COUNTER_STEP,COLLECTION_IND_TS_PAUSE);
   this.CreateCounter(COLLECTION_TICKS_COUNTER_ID,COLLECTION_TICKS_COUNTER_STEP,COLLECTION_TICKS_PAUSE);
   
   ::ResetLastError();
   #ifdef __MQL5__
      if(!::EventSetMillisecondTimer(TIMER_FREQUENCY))
        {
         ::Print(DFUN_ERR_LINE,CMessage::Text(MSG_LIB_SYS_FAILED_CREATE_TIMER),(string)::GetLastError());
         this.m_global_error=::GetLastError();
        }
   //---__MQL4__
   #else 
      if(!this.IsTester() && !::EventSetMillisecondTimer(TIMER_FREQUENCY))
        {
         ::Print(DFUN_ERR_LINE,CMessage::Text(MSG_LIB_SYS_FAILED_CREATE_TIMER),(string)::GetLastError());
         this.m_global_error=::GetLastError();
        }
   #endif 
   //---
  }
//+------------------------------------------------------------------+

Ahora el temporizador de la colección de las series de tick está creado, y es necesario implementar el bloque del trabajo con este temporizador en el temporizador de la clase:

//+------------------------------------------------------------------+
//| CEngine timer                                                    |
//+------------------------------------------------------------------+
void CEngine::OnTimer(SDataCalculate &data_calculate)
  {
//--- If this is not a tester, work with collection events by timer
   if(!this.IsTester())
     {
   //--- Timer of the collections of historical orders and deals, as well as of market orders and positions
      int index=this.CounterIndex(COLLECTION_ORD_COUNTER_ID);
      CTimerCounter* cnt1=this.m_list_counters.At(index);
      if(cnt1!=NULL)
        {
         //--- If unpaused, work with the order, deal and position collections events
         if(cnt1.IsTimeDone())
            this.TradeEventsControl();
        }
   //--- Account collection timer
      index=this.CounterIndex(COLLECTION_ACC_COUNTER_ID);
      CTimerCounter* cnt2=this.m_list_counters.At(index);
      if(cnt2!=NULL)
        {
         //--- If unpaused, work with the account collection events
         if(cnt2.IsTimeDone())
            this.AccountEventsControl();
        }
   //--- Timer 1 of the symbol collection (updating symbol quote data in the collection)
      index=this.CounterIndex(COLLECTION_SYM_COUNTER_ID1);
      CTimerCounter* cnt3=this.m_list_counters.At(index);
      if(cnt3!=NULL)
        {
         //--- If the pause is over, update quote data of all symbols in the collection
         if(cnt3.IsTimeDone())
            this.m_symbols.RefreshRates();
        }
   //--- Timer 2 of the symbol collection (updating all data of all symbols in the collection and tracking symbl and symbol search events in the market watch window)
      index=this.CounterIndex(COLLECTION_SYM_COUNTER_ID2);
      CTimerCounter* cnt4=this.m_list_counters.At(index);
      if(cnt4!=NULL)
        {
         //--- If the pause is over
         if(cnt4.IsTimeDone())
           {
            //--- update data and work with events of all symbols in the collection
            this.SymbolEventsControl();
            //--- When working with the market watch list, check the market watch window events
            if(this.m_symbols.ModeSymbolsList()==SYMBOLS_MODE_MARKET_WATCH)
               this.MarketWatchEventsControl();
           }
        }
   //--- Trading class timer
      index=this.CounterIndex(COLLECTION_REQ_COUNTER_ID);
      CTimerCounter* cnt5=this.m_list_counters.At(index);
      if(cnt5!=NULL)
        {
         //--- If unpaused, work with the list of pending requests
         if(cnt5.IsTimeDone())
            this.m_trading.OnTimer();
        }
   //--- Timeseries collection timer
      index=this.CounterIndex(COLLECTION_TS_COUNTER_ID);
      CTimerCounter* cnt6=this.m_list_counters.At(index);
      if(cnt6!=NULL)
        {
         //--- If the pause is over, work with the timeseries list (update all except the current one)
         if(cnt6.IsTimeDone())
            this.SeriesRefreshAllExceptCurrent(data_calculate);
        }
        
   //--- Timer of timeseries collection of indicator buffer data
      index=this.CounterIndex(COLLECTION_IND_TS_COUNTER_ID);
      CTimerCounter* cnt7=this.m_list_counters.At(index);
      if(cnt7!=NULL)
        {
         //--- If the pause is over, work with the timeseries list of indicator data (update all except for the current one)
         if(cnt7.IsTimeDone()) 
            this.IndicatorSeriesRefreshAll();
        }
   //--- Tick series collection timer
      index=this.CounterIndex(COLLECTION_TICKS_COUNTER_ID);
      CTimerCounter* cnt8=this.m_list_counters.At(index);
      if(cnt8!=NULL)
        {
         //--- If the pause is over, work with the tick series list (update all except the current one)
         if(cnt8.IsTimeDone())
            this.TickSeriesRefreshAllExceptCurrent();
        }
     }
//--- If this is a tester, work with collection events by tick
   else
     {
      //--- work with events of collections of orders, deals and positions by tick
      this.TradeEventsControl();
      //--- work with events of collections of accounts by tick
      this.AccountEventsControl();
      //--- update quote data of all collection symbols by tick
      this.m_symbols.RefreshRates();
      //--- work with events of all symbols in the collection by tick
      this.SymbolEventsControl();
      //--- work with the list of pending orders by tick
      this.m_trading.OnTimer();
      //--- work with the timeseries list by tick
      this.SeriesRefresh(data_calculate);
      //--- work with the timeseries list of indicator buffers by tick
      this.IndicatorSeriesRefreshAll();
      //--- work with the list of tick series by tick
      this.TickSeriesRefreshAll();
     }
  }
//+------------------------------------------------------------------+

Ahora, todas las series de tick de todos los símbolos «no nativos» van a actualizarse en el temporizador de la biblioteca.

Para actualizar la serie de tick del simbolo actual, vamos a añadir la llamada al método de actualización de la serie de tick del símbolo especificado al manejador OnTick():

//+------------------------------------------------------------------+
//| NewTick event handler                                            |
//+------------------------------------------------------------------+
void CEngine::OnTick(SDataCalculate &data_calculate,const uint required=0)
  {
//--- If this is not a EA, exit
   if(this.m_program!=PROGRAM_EXPERT)
      return;
//--- Re-create empty timeseries and update the current symbol timeseries
   this.SeriesSync(data_calculate,required);
   this.SeriesRefresh(NULL,data_calculate);
   this.TickSeriesRefresh(NULL);
//--- end
  }
//+------------------------------------------------------------------+

Ahora, la serie de tick del símbolo actual va a actualizarse cuando llegue un tick nuevo, y todas las demás series de tick de otros símbolos van a actualizarse en el temporizador de la biblioteca.

Mejorando la clase del símbolo para trabajar con la Profundidad del mercado

A partir del siguiente artículo, empezaremos a crear la funcionalidad de la biblioteca para trabajar con el DOM.

Para obtener los eventos BookEvent para cualquier símbolo, basta con suscribirse previamente a la recepción de estos eventos para este símbolo a través de la función MarketBookAdd(). Para dar de baja la suscripción a la recepción de un evento BookEvent para un determinado símbolo, hay que llamar a la función MarketBookRelease().

A cada conexión del DOM le debe corresponder su desconexión. Es fácil de hacerlo en la clase: el DOM se conecta en el constructor, y se desconecta en el destructor. Para cada símbolo separado se crea su propio objeto de símbolo. Para cada uno de estos objetos de símbolo, podemos saber exactamente cuándo el DOM está conectado y cuándo es necesario deshabilitarlo.

Abrimos la clase del objeto de símbolo en el archivo \MQL5\Include\DoEasy\Objects\Symbols\Symbol.mqh y añadimos cambios pertinentes.
En la sección privada de la clase, declaramos una variable para almacenar la bandera de la suscripción al DOM, y declaramos el destructor de la clase en la sección pública:

//+------------------------------------------------------------------+
//| Abstract symbol class                                            |
//+------------------------------------------------------------------+
class CSymbol : public CBaseObjExt
  {
private:
   struct MqlMarginRate
     {
      double         Initial;                                  // initial margin rate
      double         Maintenance;                              // maintenance margin rate
     };
   struct MqlMarginRateMode
     {
      MqlMarginRate  Long;                                     // MarginRate of long positions
      MqlMarginRate  Short;                                    // MarginRate of short positions
      MqlMarginRate  BuyStop;                                  // MarginRate of BuyStop orders
      MqlMarginRate  BuyLimit;                                 // MarginRate of BuyLimit orders
      MqlMarginRate  BuyStopLimit;                             // MarginRate of BuyStopLimit orders
      MqlMarginRate  SellStop;                                 // MarginRate of SellStop orders
      MqlMarginRate  SellLimit;                                // MarginRate of SellLimit orders
      MqlMarginRate  SellStopLimit;                            // MarginRate of SellStopLimit orders
     };
   MqlMarginRateMode m_margin_rate;                            // Margin ratio structure
   MqlBookInfo       m_book_info_array[];                      // Array of the market depth data structures
   
   long              m_long_prop[SYMBOL_PROP_INTEGER_TOTAL];   // Integer properties
   double            m_double_prop[SYMBOL_PROP_DOUBLE_TOTAL];  // Real properties
   string            m_string_prop[SYMBOL_PROP_STRING_TOTAL];  // String properties
   bool              m_is_change_trade_mode;                   // Flag of changing trading mode for a symbol
   bool              m_book_subscribed;                        // FLag of subscribing to the Depth of Market by symbol
   CTradeObj         m_trade;                                  // Trading class object
//--- Return the index of the array the symbol's (1) double and (2) string properties are located at
   int               IndexProp(ENUM_SYMBOL_PROP_DOUBLE property)  const { return(int)property-SYMBOL_PROP_INTEGER_TOTAL;                                    }
   int               IndexProp(ENUM_SYMBOL_PROP_STRING property)  const { return(int)property-SYMBOL_PROP_INTEGER_TOTAL-SYMBOL_PROP_DOUBLE_TOTAL;           }
//--- (1) Fill in all the "margin ratio" symbol properties, (2) initialize the ratios
-+/   bool              MarginRates(void);
   void              InitMarginRates(void);
//--- Reset all symbol object data
   void              Reset(void);
//--- Return the current day of the week
   ENUM_DAY_OF_WEEK  CurrentDayOfWeek(void)              const;

public:
//--- Default constructor
                     CSymbol(void){;}
//--- Destructor
                    ~CSymbol(void);
protected:
//--- Protected parametric constructor
                     CSymbol(ENUM_SYMBOL_STATUS symbol_status,const string name,const int index);

Añadimos un nuevo método que devuelve el estatus de la suscripción al DOM a los métodos del acceso simplificado de la sección pública de la clase

public:
//+------------------------------------------------------------------+
//| Methods of a simplified access to the order object properties    |
//+------------------------------------------------------------------+
//--- Integer properties
   long              Status(void)                                 const { return this.GetProperty(SYMBOL_PROP_STATUS);                                      }
   int               IndexInMarketWatch(void)                     const { return (int)this.GetProperty(SYMBOL_PROP_INDEX_MW);                               }
   bool              IsCustom(void)                               const { return (bool)this.GetProperty(SYMBOL_PROP_CUSTOM);                                }
   color             ColorBackground(void)                        const { return (color)this.GetProperty(SYMBOL_PROP_BACKGROUND_COLOR);                     }
   ENUM_SYMBOL_CHART_MODE ChartMode(void)                         const { return (ENUM_SYMBOL_CHART_MODE)this.GetProperty(SYMBOL_PROP_CHART_MODE);          }
   bool              IsExist(void)                                const { return (bool)this.GetProperty(SYMBOL_PROP_EXIST);                                 }
   bool              IsExist(const string name)                   const { return this.SymbolExists(name);                                                   }
   bool              IsSelect(void)                               const { return (bool)this.GetProperty(SYMBOL_PROP_SELECT);                                }
   bool              IsVisible(void)                              const { return (bool)this.GetProperty(SYMBOL_PROP_VISIBLE);                               }
   long              SessionDeals(void)                           const { return this.GetProperty(SYMBOL_PROP_SESSION_DEALS);                               }
   long              SessionBuyOrders(void)                       const { return this.GetProperty(SYMBOL_PROP_SESSION_BUY_ORDERS);                          }
   long              SessionSellOrders(void)                      const { return this.GetProperty(SYMBOL_PROP_SESSION_SELL_ORDERS);                         }
   long              Volume(void)                                 const { return this.GetProperty(SYMBOL_PROP_VOLUME);                                      }
   long              VolumeHigh(void)                             const { return this.GetProperty(SYMBOL_PROP_VOLUMEHIGH);                                  }
   long              VolumeLow(void)                              const { return this.GetProperty(SYMBOL_PROP_VOLUMELOW);                                   }
   long              Time(void)                                   const { return (datetime)this.GetProperty(SYMBOL_PROP_TIME);                              }
   int               Digits(void)                                 const { return (int)this.GetProperty(SYMBOL_PROP_DIGITS);                                 }
   int               DigitsLot(void)                              const { return (int)this.GetProperty(SYMBOL_PROP_DIGITS_LOTS);                            }
   int               Spread(void)                                 const { return (int)this.GetProperty(SYMBOL_PROP_SPREAD);                                 }
   bool              IsSpreadFloat(void)                          const { return (bool)this.GetProperty(SYMBOL_PROP_SPREAD_FLOAT);                          }
   int               TicksBookdepth(void)                         const { return (int)this.GetProperty(SYMBOL_PROP_TICKS_BOOKDEPTH);                        }
   bool              BookdepthSubscription(void)                  const { return (bool)this.GetProperty(SYMBOL_PROP_BOOKDEPTH_STATE);                       }
   ENUM_SYMBOL_CALC_MODE TradeCalcMode(void)                      const { return (ENUM_SYMBOL_CALC_MODE)this.GetProperty(SYMBOL_PROP_TRADE_CALC_MODE);      }
   ENUM_SYMBOL_TRADE_MODE TradeMode(void)                         const { return (ENUM_SYMBOL_TRADE_MODE)this.GetProperty(SYMBOL_PROP_TRADE_MODE);          }
   datetime          StartTime(void)                              const { return (datetime)this.GetProperty(SYMBOL_PROP_START_TIME);                        }
   datetime          ExpirationTime(void)                         const { return (datetime)this.GetProperty(SYMBOL_PROP_EXPIRATION_TIME);                   }
   int               TradeStopLevel(void)                         const { return (int)this.GetProperty(SYMBOL_PROP_TRADE_STOPS_LEVEL);                      }
   int               TradeFreezeLevel(void)                       const { return (int)this.GetProperty(SYMBOL_PROP_TRADE_FREEZE_LEVEL);                     }
   ENUM_SYMBOL_TRADE_EXECUTION TradeExecutionMode(void)           const { return (ENUM_SYMBOL_TRADE_EXECUTION)this.GetProperty(SYMBOL_PROP_TRADE_EXEMODE);  }
   ENUM_SYMBOL_SWAP_MODE SwapMode(void)                           const { return (ENUM_SYMBOL_SWAP_MODE)this.GetProperty(SYMBOL_PROP_SWAP_MODE);            }
   ENUM_DAY_OF_WEEK  SwapRollover3Days(void)                      const { return (ENUM_DAY_OF_WEEK)this.GetProperty(SYMBOL_PROP_SWAP_ROLLOVER3DAYS);        }
   bool              IsMarginHedgedUseLeg(void)                   const { return (bool)this.GetProperty(SYMBOL_PROP_MARGIN_HEDGED_USE_LEG);                 }
   int               ExpirationModeFlags(void)                    const { return (int)this.GetProperty(SYMBOL_PROP_EXPIRATION_MODE);                        }
   int               FillingModeFlags(void)                       const { return (int)this.GetProperty(SYMBOL_PROP_FILLING_MODE);                           }
   int               OrderModeFlags(void)                         const { return (int)this.GetProperty(SYMBOL_PROP_ORDER_MODE);                             }
   ENUM_SYMBOL_ORDER_GTC_MODE OrderModeGTC(void)                  const { return (ENUM_SYMBOL_ORDER_GTC_MODE)this.GetProperty(SYMBOL_PROP_ORDER_GTC_MODE);  }
   ENUM_SYMBOL_OPTION_MODE OptionMode(void)                       const { return (ENUM_SYMBOL_OPTION_MODE)this.GetProperty(SYMBOL_PROP_OPTION_MODE);        }
   ENUM_SYMBOL_OPTION_RIGHT OptionRight(void)                     const { return (ENUM_SYMBOL_OPTION_RIGHT)this.GetProperty(SYMBOL_PROP_OPTION_RIGHT);      }
//--- Real properties

En el constructor de la clase, inicializamos la bandera de la suscripción en el estado false y añadimos el valor de esta bandera a la propiedad del símbolo:

//+------------------------------------------------------------------+
//| Closed parametric constructor                                    |
//+------------------------------------------------------------------+
CSymbol::CSymbol(ENUM_SYMBOL_STATUS symbol_status,const string name,const int index)
  {
   this.m_name=name;
   this.m_book_subscribed=false;
   this.m_type=COLLECTION_SYMBOLS_ID;
   if(!this.Exist())
     {
      ::Print(DFUN_ERR_LINE,"\"",this.m_name,"\"",": ",CMessage::Text(MSG_LIB_SYS_NOT_SYMBOL_ON_SERVER));
      this.m_global_error=ERR_MARKET_UNKNOWN_SYMBOL;
     }
   bool select=::SymbolInfoInteger(this.m_name,SYMBOL_SELECT);
   ::ResetLastError();
   if(!select)
     {
      if(!this.SetToMarketWatch())
        {
         this.m_global_error=::GetLastError();
         ::Print(DFUN_ERR_LINE,"\"",this.m_name,"\": ",CMessage::Text(MSG_LIB_SYS_FAILED_PUT_SYMBOL),this.m_global_error);
        }
     }
   ::ResetLastError();
   if(!::SymbolInfoTick(this.m_name,this.m_tick))
     {
      this.m_global_error=::GetLastError();
      ::Print(DFUN_ERR_LINE,"\"",this.m_name,"\": ",CMessage::Text(MSG_LIB_SYS_NOT_GET_PRICE),this.m_global_error);
     }
//--- Initializing base object data arrays
   this.SetControlDataArraySizeLong(SYMBOL_PROP_INTEGER_TOTAL);
   this.SetControlDataArraySizeDouble(SYMBOL_PROP_DOUBLE_TOTAL);
   this.ResetChangesParams();
   this.ResetControlsParams();
   
Precios del símbolo
   this.Reset();
   this.InitMarginRates();
#ifdef __MQL5__
   ::ResetLastError();
   if(!this.MarginRates())
     {
      this.m_global_error=::GetLastError();
      ::Print(DFUN_ERR_LINE,this.Name(),": ",CMessage::Text(MSG_LIB_SYS_NOT_GET_MARGIN_RATES),this.m_global_error);
      return;
     }
#endif 
   
//--- Save integer properties
   this.m_long_prop[SYMBOL_PROP_STATUS]                                             = symbol_status;
   this.m_long_prop[SYMBOL_PROP_INDEX_MW]                                           = index;
   this.m_long_prop[SYMBOL_PROP_VOLUME]                                             = (long)this.m_tick.volume;
   this.m_long_prop[SYMBOL_PROP_SELECT]                                             = ::SymbolInfoInteger(this.m_name,SYMBOL_SELECT);
   this.m_long_prop[SYMBOL_PROP_VISIBLE]                                            = ::SymbolInfoInteger(this.m_name,SYMBOL_VISIBLE);
   this.m_long_prop[SYMBOL_PROP_SESSION_DEALS]                                      = ::SymbolInfoInteger(this.m_name,SYMBOL_SESSION_DEALS);
   this.m_long_prop[SYMBOL_PROP_SESSION_BUY_ORDERS]                                 = ::SymbolInfoInteger(this.m_name,SYMBOL_SESSION_BUY_ORDERS);
   this.m_long_prop[SYMBOL_PROP_SESSION_SELL_ORDERS]                                = ::SymbolInfoInteger(this.m_name,SYMBOL_SESSION_SELL_ORDERS);
   this.m_long_prop[SYMBOL_PROP_VOLUMEHIGH]                                         = ::SymbolInfoInteger(this.m_name,SYMBOL_VOLUMEHIGH);
   this.m_long_prop[SYMBOL_PROP_VOLUMELOW]                                          = ::SymbolInfoInteger(this.m_name,SYMBOL_VOLUMELOW);
   this.m_long_prop[SYMBOL_PROP_DIGITS]                                             = ::SymbolInfoInteger(this.m_name,SYMBOL_DIGITS);
   this.m_long_prop[SYMBOL_PROP_SPREAD]                                             = ::SymbolInfoInteger(this.m_name,SYMBOL_SPREAD);
   this.m_long_prop[SYMBOL_PROP_SPREAD_FLOAT]                                       = ::SymbolInfoInteger(this.m_name,SYMBOL_SPREAD_FLOAT);
   this.m_long_prop[SYMBOL_PROP_TICKS_BOOKDEPTH]                                    = ::SymbolInfoInteger(this.m_name,SYMBOL_TICKS_BOOKDEPTH);
   this.m_long_prop[SYMBOL_PROP_TRADE_MODE]                                         = ::SymbolInfoInteger(this.m_name,SYMBOL_TRADE_MODE);
   this.m_long_prop[SYMBOL_PROP_START_TIME]                                         = ::SymbolInfoInteger(this.m_name,SYMBOL_START_TIME);
   this.m_long_prop[SYMBOL_PROP_EXPIRATION_TIME]                                    = ::SymbolInfoInteger(this.m_name,SYMBOL_EXPIRATION_TIME);
   this.m_long_prop[SYMBOL_PROP_TRADE_STOPS_LEVEL]                                  = ::SymbolInfoInteger(this.m_name,SYMBOL_TRADE_STOPS_LEVEL);
   this.m_long_prop[SYMBOL_PROP_TRADE_FREEZE_LEVEL]                                 = ::SymbolInfoInteger(this.m_name,SYMBOL_TRADE_FREEZE_LEVEL);
   this.m_long_prop[SYMBOL_PROP_TRADE_EXEMODE]                                      = ::SymbolInfoInteger(this.m_name,SYMBOL_TRADE_EXEMODE);
   this.m_long_prop[SYMBOL_PROP_SWAP_ROLLOVER3DAYS]                                 = ::SymbolInfoInteger(this.m_name,SYMBOL_SWAP_ROLLOVER3DAYS);
   this.m_long_prop[SYMBOL_PROP_TIME]                                               = this.TickTime();
   this.m_long_prop[SYMBOL_PROP_EXIST]                                              = this.SymbolExists();
   this.m_long_prop[SYMBOL_PROP_CUSTOM]                                             = this.SymbolCustom();
   this.m_long_prop[SYMBOL_PROP_MARGIN_HEDGED_USE_LEG]                              = this.SymbolMarginHedgedUseLEG();
   this.m_long_prop[SYMBOL_PROP_ORDER_MODE]                                         = this.SymbolOrderMode();
   this.m_long_prop[SYMBOL_PROP_FILLING_MODE]                                       = this.SymbolOrderFillingMode();
   this.m_long_prop[SYMBOL_PROP_EXPIRATION_MODE]                                    = this.SymbolExpirationMode();
   this.m_long_prop[SYMBOL_PROP_ORDER_GTC_MODE]                                     = this.SymbolOrderGTCMode();
   this.m_long_prop[SYMBOL_PROP_OPTION_MODE]                                        = this.SymbolOptionMode();
   this.m_long_prop[SYMBOL_PROP_OPTION_RIGHT]                                       = this.SymbolOptionRight();
   this.m_long_prop[SYMBOL_PROP_BACKGROUND_COLOR]                                   = this.SymbolBackgroundColor();
   this.m_long_prop[SYMBOL_PROP_CHART_MODE]                                         = this.SymbolChartMode();
   this.m_long_prop[SYMBOL_PROP_TRADE_CALC_MODE]                                    = this.SymbolCalcMode();
   this.m_long_prop[SYMBOL_PROP_SWAP_MODE]                                          = this.SymbolSwapMode();
   this.m_long_prop[SYMBOL_PROP_BOOKDEPTH_STATE]                                    = this.m_book_subscribed;
//--- Save real properties
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_ASKHIGH)]                          = ::SymbolInfoDouble(this.m_name,SYMBOL_ASKHIGH);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_ASKLOW)]                           = ::SymbolInfoDouble(this.m_name,SYMBOL_ASKLOW);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_LASTHIGH)]                         = ::SymbolInfoDouble(this.m_name,SYMBOL_LASTHIGH);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_LASTLOW)]                          = ::SymbolInfoDouble(this.m_name,SYMBOL_LASTLOW);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_POINT)]                            = ::SymbolInfoDouble(this.m_name,SYMBOL_POINT);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_TRADE_TICK_VALUE)]                 = ::SymbolInfoDouble(this.m_name,SYMBOL_TRADE_TICK_VALUE);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_TRADE_TICK_VALUE_PROFIT)]          = ::SymbolInfoDouble(this.m_name,SYMBOL_TRADE_TICK_VALUE_PROFIT);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_TRADE_TICK_VALUE_LOSS)]            = ::SymbolInfoDouble(this.m_name,SYMBOL_TRADE_TICK_VALUE_LOSS);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_TRADE_TICK_SIZE)]                  = ::SymbolInfoDouble(this.m_name,SYMBOL_TRADE_TICK_SIZE);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_TRADE_CONTRACT_SIZE)]              = ::SymbolInfoDouble(this.m_name,SYMBOL_TRADE_CONTRACT_SIZE);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_VOLUME_MIN)]                       = ::SymbolInfoDouble(this.m_name,SYMBOL_VOLUME_MIN);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_VOLUME_MAX)]                       = ::SymbolInfoDouble(this.m_name,SYMBOL_VOLUME_MAX);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_VOLUME_STEP)]                      = ::SymbolInfoDouble(this.m_name,SYMBOL_VOLUME_STEP);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_VOLUME_LIMIT)]                     = ::SymbolInfoDouble(this.m_name,SYMBOL_VOLUME_LIMIT);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_SWAP_LONG)]                        = ::SymbolInfoDouble(this.m_name,SYMBOL_SWAP_LONG);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_SWAP_SHORT)]                       = ::SymbolInfoDouble(this.m_name,SYMBOL_SWAP_SHORT);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_MARGIN_INITIAL)]                   = ::SymbolInfoDouble(this.m_name,SYMBOL_MARGIN_INITIAL);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_MARGIN_MAINTENANCE)]               = ::SymbolInfoDouble(this.m_name,SYMBOL_MARGIN_MAINTENANCE);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_SESSION_VOLUME)]                   = ::SymbolInfoDouble(this.m_name,SYMBOL_SESSION_VOLUME);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_SESSION_TURNOVER)]                 = ::SymbolInfoDouble(this.m_name,SYMBOL_SESSION_TURNOVER);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_SESSION_INTEREST)]                 = ::SymbolInfoDouble(this.m_name,SYMBOL_SESSION_INTEREST);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_SESSION_BUY_ORDERS_VOLUME)]        = ::SymbolInfoDouble(this.m_name,SYMBOL_SESSION_BUY_ORDERS_VOLUME);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_SESSION_SELL_ORDERS_VOLUME)]       = ::SymbolInfoDouble(this.m_name,SYMBOL_SESSION_SELL_ORDERS_VOLUME);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_SESSION_OPEN)]                     = ::SymbolInfoDouble(this.m_name,SYMBOL_SESSION_OPEN);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_SESSION_CLOSE)]                    = ::SymbolInfoDouble(this.m_name,SYMBOL_SESSION_CLOSE);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_SESSION_AW)]                       = ::SymbolInfoDouble(this.m_name,SYMBOL_SESSION_AW);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_SESSION_PRICE_SETTLEMENT)]         = ::SymbolInfoDouble(this.m_name,SYMBOL_SESSION_PRICE_SETTLEMENT);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_SESSION_PRICE_LIMIT_MIN)]          = ::SymbolInfoDouble(this.m_name,SYMBOL_SESSION_PRICE_LIMIT_MIN);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_SESSION_PRICE_LIMIT_MAX)]          = ::SymbolInfoDouble(this.m_name,SYMBOL_SESSION_PRICE_LIMIT_MAX);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_BID)]                              = this.m_tick.bid;
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_ASK)]                              = this.m_tick.ask;
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_LAST)]                             = this.m_tick.last;
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_BIDHIGH)]                          = this.SymbolBidHigh();
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_BIDLOW)]                           = this.SymbolBidLow();
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_VOLUME_REAL)]                      = this.SymbolVolumeReal();
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_VOLUMEHIGH_REAL)]                  = this.SymbolVolumeHighReal();
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_VOLUMELOW_REAL)]                   = this.SymbolVolumeLowReal();
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_OPTION_STRIKE)]                    = this.SymbolOptionStrike();
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_TRADE_ACCRUED_INTEREST)]           = this.SymbolTradeAccruedInterest();
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_TRADE_FACE_VALUE)]                 = this.SymbolTradeFaceValue();
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_TRADE_LIQUIDITY_RATE)]             = this.SymbolTradeLiquidityRate();
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_MARGIN_HEDGED)]                    = this.SymbolMarginHedged();
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_MARGIN_LONG_INITIAL)]              = this.m_margin_rate.Long.Initial;
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_MARGIN_BUY_STOP_INITIAL)]          = this.m_margin_rate.BuyStop.Initial;
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_MARGIN_BUY_LIMIT_INITIAL)]         = this.m_margin_rate.BuyLimit.Initial;
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_MARGIN_BUY_STOPLIMIT_INITIAL)]     = this.m_margin_rate.BuyStopLimit.Initial;
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_MARGIN_LONG_MAINTENANCE)]          = this.m_margin_rate.Long.Maintenance;
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_MARGIN_BUY_STOP_MAINTENANCE)]      = this.m_margin_rate.BuyStop.Maintenance;
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_MARGIN_BUY_LIMIT_MAINTENANCE)]     = this.m_margin_rate.BuyLimit.Maintenance;
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_MARGIN_BUY_STOPLIMIT_MAINTENANCE)] = this.m_margin_rate.BuyStopLimit.Maintenance;
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_MARGIN_SHORT_INITIAL)]             = this.m_margin_rate.Short.Initial;
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_MARGIN_SELL_STOP_INITIAL)]         = this.m_margin_rate.SellStop.Initial;
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_MARGIN_SELL_LIMIT_INITIAL)]        = this.m_margin_rate.SellLimit.Initial;
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_MARGIN_SELL_STOPLIMIT_INITIAL)]    = this.m_margin_rate.SellStopLimit.Initial;
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_MARGIN_SHORT_MAINTENANCE)]         = this.m_margin_rate.Short.Maintenance;
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_MARGIN_SELL_STOP_MAINTENANCE)]     = this.m_margin_rate.SellStop.Maintenance;
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_MARGIN_SELL_LIMIT_MAINTENANCE)]    = this.m_margin_rate.SellLimit.Maintenance;
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_MARGIN_SELL_STOPLIMIT_MAINTENANCE)]= this.m_margin_rate.SellStopLimit.Maintenance;
//--- Save string properties
   this.m_string_prop[this.IndexProp(SYMBOL_PROP_NAME)]                             = this.m_name;
   this.m_string_prop[this.IndexProp(SYMBOL_PROP_CURRENCY_BASE)]                    = ::SymbolInfoString(this.m_name,SYMBOL_CURRENCY_BASE);
   this.m_string_prop[this.IndexProp(SYMBOL_PROP_CURRENCY_PROFIT)]                  = ::SymbolInfoString(this.m_name,SYMBOL_CURRENCY_PROFIT);
   this.m_string_prop[this.IndexProp(SYMBOL_PROP_CURRENCY_MARGIN)]                  = ::SymbolInfoString(this.m_name,SYMBOL_CURRENCY_MARGIN);
   this.m_string_prop[this.IndexProp(SYMBOL_PROP_DESCRIPTION)]                      = ::SymbolInfoString(this.m_name,SYMBOL_DESCRIPTION);
   this.m_string_prop[this.IndexProp(SYMBOL_PROP_PATH)]                             = ::SymbolInfoString(this.m_name,SYMBOL_PATH);
   this.m_string_prop[this.IndexProp(SYMBOL_PROP_BASIS)]                            = this.SymbolBasis();
   this.m_string_prop[this.IndexProp(SYMBOL_PROP_BANK)]                             = this.SymbolBank();
   this.m_string_prop[this.IndexProp(SYMBOL_PROP_ISIN)]                             = this.SymbolISIN();
   this.m_string_prop[this.IndexProp(SYMBOL_PROP_FORMULA)]                          = this.SymbolFormula();
   this.m_string_prop[this.IndexProp(SYMBOL_PROP_PAGE)]                             = this.SymbolPage();
   this.m_string_prop[this.IndexProp(SYMBOL_PROP_CATEGORY)]                         = this.SymbolCategory();
   this.m_string_prop[this.IndexProp(SYMBOL_PROP_EXCHANGE)]                         = this.SymbolExchange();
//--- Save additional integer properties
   this.m_long_prop[SYMBOL_PROP_DIGITS_LOTS]                                        = this.SymbolDigitsLot();
   
//--- Fill in the symbol current data
   for(int i=0;i<SYMBOL_PROP_INTEGER_TOTAL;i++)
      this.m_long_prop_event[i][3]=this.m_long_prop[i];
   for(int i=0;i<SYMBOL_PROP_DOUBLE_TOTAL;i++)
      this.m_double_prop_event[i][3]=this.m_double_prop[i];
   
//--- Update the base object data and search for changes
   CBaseObjExt::Refresh();
//---
   if(!select)
      this.RemoveFromMarketWatch();

//--- Initializing default values of a trading object
   this.m_trade.Init(this.Name(),0,this.LotsMin(),5,0,0,false,this.GetCorrectTypeFilling(),this.GetCorrectTypeExpiration(),LOG_LEVEL_ERROR_MSG);
  }
//+------------------------------------------------------------------+

Implementación del destructor de clase:

//+------------------------------------------------------------------+
//| Destructor                                                       |
//+------------------------------------------------------------------+
CSymbol::~CSymbol(void)
  {
   if(this.m_book_subscribed)
      this.BookClose();
  }
//+------------------------------------------------------------------+

Si la bandera de la suscripción al DOM está habilitada, damos de baja la transmisión del DOM.

Así, para cualquier símbolo se cumplirá la regla «1 suscripción = una baja». Porque después de que el trabajo del programa se termine, el método de la baja de la suscripción será invocado en el destructor de la clase sólo si la suscripción al símbolo ha sido activada. Eso funciona para cada uno de los símbolos utilizados en el programa con la suscripción activada.

El bloque del código para visualizar la descripción de la propiedad del estado de la suscripción al DOM se añade al método que devuelve la descripción de la propiedad entera del símbolo:

//+------------------------------------------------------------------+
//| Return the description of the symbol integer property            |
//+------------------------------------------------------------------+
string CSymbol::GetPropertyDescription(ENUM_SYMBOL_PROP_INTEGER property)
  {
   return
     (
      property==SYMBOL_PROP_STATUS              ?  CMessage::Text(MSG_ORD_STATUS)+
         (!this.SupportProperty(property) ?  ": "+CMessage::Text(MSG_LIB_PROP_NOT_SUPPORTED) :
          ": "+this.GetStatusDescription()
         )  :
      property==SYMBOL_PROP_INDEX_MW            ?  CMessage::Text(MSG_SYM_PROP_INDEX)+
         (!this.SupportProperty(property) ?  ": "+CMessage::Text(MSG_LIB_PROP_NOT_SUPPORTED) :
          ": "+(string)this.GetProperty(property)
         )  :
      property==SYMBOL_PROP_CUSTOM              ?  CMessage::Text(MSG_SYM_PROP_CUSTOM)+
         (!this.SupportProperty(property) ?  ": "+CMessage::Text(MSG_LIB_PROP_NOT_SUPPORTED) :
          ": "+(this.GetProperty(property)   ?  CMessage::Text(MSG_LIB_TEXT_YES) : CMessage::Text(MSG_LIB_TEXT_NO))
         )  :
      property==SYMBOL_PROP_CHART_MODE          ?  CMessage::Text(MSG_SYM_PROP_CHART_MODE)+
         (!this.SupportProperty(property) ?  ": "+CMessage::Text(MSG_LIB_PROP_NOT_SUPPORTED) :
          ": "+this.GetChartModeDescription()
         )  :
      property==SYMBOL_PROP_EXIST               ?  CMessage::Text(MSG_SYM_PROP_EXIST)+
         (!this.SupportProperty(property) ?  ": "+CMessage::Text(MSG_LIB_PROP_NOT_SUPPORTED) :
          ": "+(this.GetProperty(property)   ?  CMessage::Text(MSG_LIB_TEXT_YES) : CMessage::Text(MSG_LIB_TEXT_NO))
         )  :
      property==SYMBOL_PROP_SELECT  ?  CMessage::Text(MSG_SYM_PROP_SELECT)+
         (!this.SupportProperty(property) ?  ": "+CMessage::Text(MSG_LIB_PROP_NOT_SUPPORTED) :
          ": "+(this.GetProperty(property)   ?  CMessage::Text(MSG_LIB_TEXT_YES) : CMessage::Text(MSG_LIB_TEXT_NO))
         )  :
      property==SYMBOL_PROP_VISIBLE ?  CMessage::Text(MSG_SYM_PROP_VISIBLE)+
         (!this.SupportProperty(property) ?  ": "+CMessage::Text(MSG_LIB_PROP_NOT_SUPPORTED) :
          ": "+(this.GetProperty(property)   ?  CMessage::Text(MSG_LIB_TEXT_YES) : CMessage::Text(MSG_LIB_TEXT_NO))
         )  :
      property==SYMBOL_PROP_SESSION_DEALS       ?  CMessage::Text(MSG_SYM_PROP_SESSION_DEALS)+
         (!this.SupportProperty(property)    ?  ": "+CMessage::Text(MSG_LIB_PROP_NOT_SUPPORTED) :
          ": "+ #ifdef __MQL5__(string)this.GetProperty(property) #else CMessage::Text(MSG_LIB_PROP_NOT_SUPPORTED_MQL4) #endif 
         )  :
      property==SYMBOL_PROP_SESSION_BUY_ORDERS  ?  CMessage::Text(MSG_SYM_PROP_SESSION_BUY_ORDERS)+
         (!this.SupportProperty(property) ?  ": "+CMessage::Text(MSG_LIB_PROP_NOT_SUPPORTED) :
          ": "+ #ifdef __MQL5__(string)this.GetProperty(property) #else CMessage::Text(MSG_LIB_PROP_NOT_SUPPORTED_MQL4) #endif 
         )  :
      property==SYMBOL_PROP_SESSION_SELL_ORDERS ?  CMessage::Text(MSG_SYM_PROP_SESSION_SELL_ORDERS)+
         (!this.SupportProperty(property) ?  ": "+CMessage::Text(MSG_LIB_PROP_NOT_SUPPORTED) :
          ": "+ #ifdef __MQL5__(string)this.GetProperty(property) #else CMessage::Text(MSG_LIB_PROP_NOT_SUPPORTED_MQL4) #endif 
         )  :
      property==SYMBOL_PROP_VOLUME              ?  CMessage::Text(MSG_SYM_PROP_VOLUME)+
         (!this.SupportProperty(property) ?  ": "+CMessage::Text(MSG_LIB_PROP_NOT_SUPPORTED) :
          ": "+ #ifdef __MQL5__(string)this.GetProperty(property) #else CMessage::Text(MSG_LIB_PROP_NOT_SUPPORTED_MQL4) #endif 
         )  :
      property==SYMBOL_PROP_VOLUMEHIGH          ?  CMessage::Text(MSG_SYM_PROP_VOLUMEHIGH)+
         (!this.SupportProperty(property) ?  ": "+CMessage::Text(MSG_LIB_PROP_NOT_SUPPORTED) :
          ": "+ #ifdef __MQL5__(string)this.GetProperty(property) #else CMessage::Text(MSG_LIB_PROP_NOT_SUPPORTED_MQL4) #endif 
         )  :
      property==SYMBOL_PROP_VOLUMELOW           ?  CMessage::Text(MSG_SYM_PROP_VOLUMELOW)+
         (!this.SupportProperty(property) ?  ": "+CMessage::Text(MSG_LIB_PROP_NOT_SUPPORTED) :
          ": "+ #ifdef __MQL5__(string)this.GetProperty(property) #else CMessage::Text(MSG_LIB_PROP_NOT_SUPPORTED_MQL4) #endif 
         )  :
      property==SYMBOL_PROP_TIME                ?  CMessage::Text(MSG_SYM_PROP_TIME)+
         (!this.SupportProperty(property) ?  ": "+CMessage::Text(MSG_LIB_PROP_NOT_SUPPORTED) :
          ": "+(this.GetProperty(property)==0 ? "("+CMessage::Text(MSG_LIB_SYS_NO_TICKS_YET)+")" : TimeMSCtoString(this.GetProperty(property)))
         )  :
      property==SYMBOL_PROP_DIGITS              ?  CMessage::Text(MSG_SYM_PROP_DIGITS)+
         (!this.SupportProperty(property) ?  ": "+CMessage::Text(MSG_LIB_PROP_NOT_SUPPORTED) :
          ": "+(string)this.GetProperty(property)
         )  :
      property==SYMBOL_PROP_DIGITS_LOTS         ?  CMessage::Text(MSG_SYM_PROP_DIGITS_LOTS)+
         (!this.SupportProperty(property) ?  ": "+CMessage::Text(MSG_LIB_PROP_NOT_SUPPORTED) :
          ": "+(string)this.GetProperty(property)
         )  :
      property==SYMBOL_PROP_SPREAD              ?  CMessage::Text(MSG_SYM_PROP_SPREAD)+
         (!this.SupportProperty(property) ?  ": "+CMessage::Text(MSG_LIB_PROP_NOT_SUPPORTED) :
          ": "+(string)this.GetProperty(property)
         )  :
      property==SYMBOL_PROP_SPREAD_FLOAT        ?  CMessage::Text(MSG_SYM_PROP_SPREAD_FLOAT)+
         (!this.SupportProperty(property) ?  ": "+CMessage::Text(MSG_LIB_PROP_NOT_SUPPORTED) :
          ": "+(this.GetProperty(property)   ?  CMessage::Text(MSG_LIB_TEXT_YES) : CMessage::Text(MSG_LIB_TEXT_YES))
         )  :
      property==SYMBOL_PROP_TICKS_BOOKDEPTH     ?  CMessage::Text(MSG_SYM_PROP_TICKS_BOOKDEPTH)+
         (!this.SupportProperty(property) ?  ": "+CMessage::Text(MSG_LIB_PROP_NOT_SUPPORTED) :
          ": "+ #ifdef __MQL5__(string)this.GetProperty(property) #else CMessage::Text(MSG_LIB_PROP_NOT_SUPPORTED_MQL4) #endif 
         )  :
      property==SYMBOL_PROP_BOOKDEPTH_STATE     ?  CMessage::Text(MSG_SYM_SYMBOLS_MODE_BOOK)+
         (!this.SupportProperty(property) ?  ": "+CMessage::Text(MSG_LIB_PROP_NOT_SUPPORTED) :
          ": "+ #ifdef __MQL5__
                  (this.GetProperty(property) ? CMessage::Text(MSG_LIB_TEXT_YES) : CMessage::Text(MSG_LIB_TEXT_NO)) 
                #else 
                  CMessage::Text(MSG_LIB_PROP_NOT_SUPPORTED_MQL4) 
                #endif 
         )  :
      property==SYMBOL_PROP_TRADE_CALC_MODE     ?  CMessage::Text(MSG_SYM_PROP_TRADE_CALC_MODE)+
         (!this.SupportProperty(property) ?  ": "+CMessage::Text(MSG_LIB_PROP_NOT_SUPPORTED) :
          ": "+this.GetCalcModeDescription()
         )  :
      property==SYMBOL_PROP_TRADE_MODE ?  CMessage::Text(MSG_SYM_PROP_TRADE_MODE)+
         (!this.SupportProperty(property) ?  ": "+CMessage::Text(MSG_LIB_PROP_NOT_SUPPORTED) :
          ": "+this.GetTradeModeDescription()
         )  :
      property==SYMBOL_PROP_START_TIME          ?  CMessage::Text(MSG_SYM_PROP_START_TIME)+
         (!this.SupportProperty(property) ?  ": "+CMessage::Text(MSG_LIB_PROP_NOT_SUPPORTED) :
         (this.GetProperty(property)==0  ?  ": ("+CMessage::Text(MSG_LIB_PROP_EMPTY)+")" : ": "+TimeMSCtoString(this.GetProperty(property)*1000))
         )  :
      property==SYMBOL_PROP_EXPIRATION_TIME     ?  CMessage::Text(MSG_SYM_PROP_EXPIRATION_TIME)+
         (!this.SupportProperty(property) ?  ": "+CMessage::Text(MSG_LIB_PROP_NOT_SUPPORTED) :
         (this.GetProperty(property)==0  ?  ": ("+CMessage::Text(MSG_LIB_PROP_EMPTY)+")" : ": "+TimeMSCtoString(this.GetProperty(property)*1000))
         )  :
      property==SYMBOL_PROP_TRADE_STOPS_LEVEL   ?  CMessage::Text(MSG_SYM_PROP_TRADE_STOPS_LEVEL)+
         (!this.SupportProperty(property) ?  ": "+CMessage::Text(MSG_LIB_PROP_NOT_SUPPORTED) :
          ": "+(string)this.GetProperty(property)
         )  :
      property==SYMBOL_PROP_TRADE_FREEZE_LEVEL  ?  CMessage::Text(MSG_SYM_PROP_TRADE_FREEZE_LEVEL)+
         (!this.SupportProperty(property)    ?  ": "+CMessage::Text(MSG_LIB_PROP_NOT_SUPPORTED) :
          ": "+(string)this.GetProperty(property)
         )  :
      property==SYMBOL_PROP_TRADE_EXEMODE       ?  CMessage::Text(MSG_SYM_PROP_TRADE_EXEMODE)+
         (!this.SupportProperty(property) ?  ": "+CMessage::Text(MSG_LIB_PROP_NOT_SUPPORTED) :
          ": "+this.GetTradeExecDescription()
         )  :
      property==SYMBOL_PROP_SWAP_MODE           ?  CMessage::Text(MSG_SYM_PROP_SWAP_MODE)+
         (!this.SupportProperty(property) ?  ": "+CMessage::Text(MSG_LIB_PROP_NOT_SUPPORTED) :
          ": "+this.GetSwapModeDescription()
         )  :
      property==SYMBOL_PROP_SWAP_ROLLOVER3DAYS  ?  CMessage::Text(MSG_SYM_PROP_SWAP_ROLLOVER3DAYS)+
         (!this.SupportProperty(property) ?  ": "+CMessage::Text(MSG_LIB_PROP_NOT_SUPPORTED) :
          ": "+DayOfWeekDescription(this.SwapRollover3Days())
         )  :
      property==SYMBOL_PROP_MARGIN_HEDGED_USE_LEG  ?  CMessage::Text(MSG_SYM_PROP_MARGIN_HEDGED_USE_LEG)+
         (!this.SupportProperty(property) ?  ": "+CMessage::Text(MSG_LIB_PROP_NOT_SUPPORTED)   :
          ": "+(this.GetProperty(property)   ?  CMessage::Text(MSG_LIB_TEXT_YES) : CMessage::Text(MSG_LIB_TEXT_NO))
         )  :
      property==SYMBOL_PROP_EXPIRATION_MODE     ?  CMessage::Text(MSG_SYM_PROP_EXPIRATION_MODE)+
         (!this.SupportProperty(property) ?  ": "+CMessage::Text(MSG_LIB_PROP_NOT_SUPPORTED) :
          ": "+this.GetExpirationModeFlagsDescription()
         )  :
      property==SYMBOL_PROP_FILLING_MODE        ?  CMessage::Text(MSG_SYM_PROP_FILLING_MODE)+
         (!this.SupportProperty(property) ?  ": "+CMessage::Text(MSG_LIB_PROP_NOT_SUPPORTED) :
          ": "+this.GetFillingModeFlagsDescription()
         )  :
      property==SYMBOL_PROP_ORDER_MODE          ?  CMessage::Text(MSG_SYM_PROP_ORDER_MODE)+
         (!this.SupportProperty(property) ?  ": "+CMessage::Text(MSG_LIB_PROP_NOT_SUPPORTED) :
          ": "+this.GetOrderModeFlagsDescription()
         )  :
      property==SYMBOL_PROP_ORDER_GTC_MODE      ?  CMessage::Text(MSG_SYM_PROP_ORDER_GTC_MODE)+
         (!this.SupportProperty(property) ?  ": "+CMessage::Text(MSG_LIB_PROP_NOT_SUPPORTED) :
          ": "+this.GetOrderGTCModeDescription()
         )  :
      property==SYMBOL_PROP_OPTION_MODE         ?  CMessage::Text(MSG_SYM_PROP_OPTION_MODE)+
         (!this.SupportProperty(property) ?  ": "+CMessage::Text(MSG_LIB_PROP_NOT_SUPPORTED) :
          ": "+this.GetOptionTypeDescription()
         )  :
      property==SYMBOL_PROP_OPTION_RIGHT        ?  CMessage::Text(MSG_SYM_PROP_OPTION_RIGHT)+
         (!this.SupportProperty(property) ?  ": "+CMessage::Text(MSG_LIB_PROP_NOT_SUPPORTED) :
          ": "+this.GetOptionRightDescription()
         )  :
      property==SYMBOL_PROP_BACKGROUND_COLOR    ?  CMessage::Text(MSG_SYM_PROP_BACKGROUND_COLOR)+
         (!this.SupportProperty(property) ?  ": "+CMessage::Text(MSG_LIB_PROP_NOT_SUPPORTED) :
         #ifdef __MQL5__
         (this.GetProperty(property)==CLR_DEFAULT || this.GetProperty(property)==CLR_NONE ?  ": ("+CMessage::Text(MSG_LIB_PROP_EMPTY)+")" : ": "+::ColorToString((color)this.GetProperty(property),true))
         #else ": "+CMessage::Text(MSG_LIB_PROP_NOT_SUPPORTED_MQL4) #endif 
         )  :
      ""
     );
  }
//+------------------------------------------------------------------+

Método para realizar la suscripción al DOM:

//+------------------------------------------------------------------+
//| Subscribe to the Depth of Market                                 |
//+------------------------------------------------------------------+
bool CSymbol::BookAdd(void)
  {
   this.m_book_subscribed=(#ifdef __MQL5__ ::MarketBookAdd(this.m_name) #else false #endif);
   if(this.m_book_subscribed)
     {
      this.m_long_prop[SYMBOL_PROP_BOOKDEPTH_STATE]=this.m_book_subscribed;
      ::Print(CMessage::Text(MSG_SYM_SYMBOLS_BOOK_ADD)+" "+this.m_name);
     }
   return this.m_book_subscribed;
  }
//+------------------------------------------------------------------+

La variable m_book_subscribed, que almacena la bandera del estado de la suscripción, recibe el resultado del trabajo de la función MarketBookAdd() que asegura la apertura del DOM según el instrumento especificado y realiza la suscripción a recibir notificaciones sobre el cambio de este DOM.
Si la suscripción ha sido realizada, visualizamos el mensaje apropiado.
El método devuelve el resultado escrito en m_book_subscribed.

Método para cerrar el DOM:

//+------------------------------------------------------------------+
//| Close the market depth                                           |
//+------------------------------------------------------------------+
bool CSymbol::BookClose(void)
  {
//--- If the DOM subscription flag is off, subscription is disabled (or not enabled yet). Return 'true'
   if(!this.m_book_subscribed)
      return true;
//--- Save the result of unsubscribing from the DOM
   bool res=( #ifdef __MQL5__ ::MarketBookRelease(this.m_name) #else true #endif );
//--- If unsubscribed successfully, reset the DOM subscription flag and write the status to the object property
   if(res)
     {
      this.m_long_prop[SYMBOL_PROP_BOOKDEPTH_STATE]=this.m_book_subscribed=false;
      ::Print(CMessage::Text(MSG_SYM_SYMBOLS_BOOK_DEL)+" "+this.m_name);
     }
//--- Return the result of unsubscribing from DOM
   return res;
  }
//+------------------------------------------------------------------+

La lógica del método está descrita en los comentarios al código. Hay que aclarar que el método debe devolver la bandera que indica en la baja de la suscripción al DOM. Si la suscripción no ha sido realizada antes, el método devolverá inmediatamente true, lo que indica en una baja con éxito, aunque en realidad no había ninguna suscripción.

Al método de la actualización de todas las propiedades del símbolo le añadimos la actualización del estado de la suscripción que corresponde al estado de la bandera en la variable m_book_subscribed:

//+------------------------------------------------------------------+
//| Update all symbol data                                           |
//+------------------------------------------------------------------+
void CSymbol::Refresh(void)
  {
//--- Update quote data
   if(!this.RefreshRates())
      return;
#ifdef __MQL5__
   ::ResetLastError();
   if(!this.MarginRates())
     {
      this.m_global_error=::GetLastError();
      return;
     }
#endif 
//--- Initialize event data
   this.m_is_event=false;
   this.m_hash_sum=0;
//--- Update integer properties
   this.m_long_prop[SYMBOL_PROP_SELECT]                                             = ::SymbolInfoInteger(this.m_name,SYMBOL_SELECT);
   this.m_long_prop[SYMBOL_PROP_VISIBLE]                                            = ::SymbolInfoInteger(this.m_name,SYMBOL_VISIBLE);
   this.m_long_prop[SYMBOL_PROP_SESSION_DEALS]                                      = ::SymbolInfoInteger(this.m_name,SYMBOL_SESSION_DEALS);
   this.m_long_prop[SYMBOL_PROP_SESSION_BUY_ORDERS]                                 = ::SymbolInfoInteger(this.m_name,SYMBOL_SESSION_BUY_ORDERS);
   this.m_long_prop[SYMBOL_PROP_SESSION_SELL_ORDERS]                                = ::SymbolInfoInteger(this.m_name,SYMBOL_SESSION_SELL_ORDERS);
   this.m_long_prop[SYMBOL_PROP_VOLUMEHIGH]                                         = ::SymbolInfoInteger(this.m_name,SYMBOL_VOLUMEHIGH);
   this.m_long_prop[SYMBOL_PROP_VOLUMELOW]                                          = ::SymbolInfoInteger(this.m_name,SYMBOL_VOLUMELOW);
   this.m_long_prop[SYMBOL_PROP_SPREAD]                                             = ::SymbolInfoInteger(this.m_name,SYMBOL_SPREAD);
   this.m_long_prop[SYMBOL_PROP_TICKS_BOOKDEPTH]                                    = ::SymbolInfoInteger(this.m_name,SYMBOL_TICKS_BOOKDEPTH);
   this.m_long_prop[SYMBOL_PROP_START_TIME]                                         = ::SymbolInfoInteger(this.m_name,SYMBOL_START_TIME);
   this.m_long_prop[SYMBOL_PROP_EXPIRATION_TIME]                                    = ::SymbolInfoInteger(this.m_name,SYMBOL_EXPIRATION_TIME);
   this.m_long_prop[SYMBOL_PROP_TRADE_STOPS_LEVEL]                                  = ::SymbolInfoInteger(this.m_name,SYMBOL_TRADE_STOPS_LEVEL);
   this.m_long_prop[SYMBOL_PROP_TRADE_FREEZE_LEVEL]                                 = ::SymbolInfoInteger(this.m_name,SYMBOL_TRADE_FREEZE_LEVEL);
   this.m_long_prop[SYMBOL_PROP_BACKGROUND_COLOR]                                   = this.SymbolBackgroundColor();
   this.m_long_prop[SYMBOL_PROP_BOOKDEPTH_STATE]                                    = this.m_book_subscribed;
   
//--- Update real properties
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_TRADE_TICK_VALUE)]                 = ::SymbolInfoDouble(this.m_name,SYMBOL_TRADE_TICK_VALUE);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_TRADE_TICK_VALUE_PROFIT)]          = ::SymbolInfoDouble(this.m_name,SYMBOL_TRADE_TICK_VALUE_PROFIT);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_TRADE_TICK_VALUE_LOSS)]            = ::SymbolInfoDouble(this.m_name,SYMBOL_TRADE_TICK_VALUE_LOSS);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_TRADE_TICK_SIZE)]                  = ::SymbolInfoDouble(this.m_name,SYMBOL_TRADE_TICK_SIZE);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_TRADE_CONTRACT_SIZE)]              = ::SymbolInfoDouble(this.m_name,SYMBOL_TRADE_CONTRACT_SIZE);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_VOLUME_MIN)]                       = ::SymbolInfoDouble(this.m_name,SYMBOL_VOLUME_MIN);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_VOLUME_MAX)]                       = ::SymbolInfoDouble(this.m_name,SYMBOL_VOLUME_MAX);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_VOLUME_STEP)]                      = ::SymbolInfoDouble(this.m_name,SYMBOL_VOLUME_STEP);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_VOLUME_LIMIT)]                     = ::SymbolInfoDouble(this.m_name,SYMBOL_VOLUME_LIMIT);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_SWAP_LONG)]                        = ::SymbolInfoDouble(this.m_name,SYMBOL_SWAP_LONG);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_SWAP_SHORT)]                       = ::SymbolInfoDouble(this.m_name,SYMBOL_SWAP_SHORT);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_MARGIN_INITIAL)]                   = ::SymbolInfoDouble(this.m_name,SYMBOL_MARGIN_INITIAL);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_MARGIN_MAINTENANCE)]               = ::SymbolInfoDouble(this.m_name,SYMBOL_MARGIN_MAINTENANCE);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_SESSION_VOLUME)]                   = ::SymbolInfoDouble(this.m_name,SYMBOL_SESSION_VOLUME);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_SESSION_TURNOVER)]                 = ::SymbolInfoDouble(this.m_name,SYMBOL_SESSION_TURNOVER);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_SESSION_INTEREST)]                 = ::SymbolInfoDouble(this.m_name,SYMBOL_SESSION_INTEREST);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_SESSION_BUY_ORDERS_VOLUME)]        = ::SymbolInfoDouble(this.m_name,SYMBOL_SESSION_BUY_ORDERS_VOLUME);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_SESSION_SELL_ORDERS_VOLUME)]       = ::SymbolInfoDouble(this.m_name,SYMBOL_SESSION_SELL_ORDERS_VOLUME);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_SESSION_OPEN)]                     = ::SymbolInfoDouble(this.m_name,SYMBOL_SESSION_OPEN);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_SESSION_CLOSE)]                    = ::SymbolInfoDouble(this.m_name,SYMBOL_SESSION_CLOSE);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_SESSION_AW)]                       = ::SymbolInfoDouble(this.m_name,SYMBOL_SESSION_AW);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_SESSION_PRICE_SETTLEMENT)]         = ::SymbolInfoDouble(this.m_name,SYMBOL_SESSION_PRICE_SETTLEMENT);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_SESSION_PRICE_LIMIT_MIN)]          = ::SymbolInfoDouble(this.m_name,SYMBOL_SESSION_PRICE_LIMIT_MIN);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_SESSION_PRICE_LIMIT_MAX)]          = ::SymbolInfoDouble(this.m_name,SYMBOL_SESSION_PRICE_LIMIT_MAX);
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_VOLUME_REAL)]                      = this.SymbolVolumeReal();
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_VOLUMEHIGH_REAL)]                  = this.SymbolVolumeHighReal();
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_VOLUMELOW_REAL)]                   = this.SymbolVolumeLowReal();
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_OPTION_STRIKE)]                    = this.SymbolOptionStrike();
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_TRADE_ACCRUED_INTEREST)]           = this.SymbolTradeAccruedInterest();
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_TRADE_FACE_VALUE)]                 = this.SymbolTradeFaceValue();
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_TRADE_LIQUIDITY_RATE)]             = this.SymbolTradeLiquidityRate();
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_MARGIN_HEDGED)]                    = this.SymbolMarginHedged();
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_MARGIN_LONG_INITIAL)]              = this.m_margin_rate.Long.Initial;
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_MARGIN_BUY_STOP_INITIAL)]          = this.m_margin_rate.BuyStop.Initial;
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_MARGIN_BUY_LIMIT_INITIAL)]         = this.m_margin_rate.BuyLimit.Initial;
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_MARGIN_BUY_STOPLIMIT_INITIAL)]     = this.m_margin_rate.BuyStopLimit.Initial;
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_MARGIN_LONG_MAINTENANCE)]          = this.m_margin_rate.Long.Maintenance;
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_MARGIN_BUY_STOP_MAINTENANCE)]      = this.m_margin_rate.BuyStop.Maintenance;
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_MARGIN_BUY_LIMIT_MAINTENANCE)]     = this.m_margin_rate.BuyLimit.Maintenance;
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_MARGIN_BUY_STOPLIMIT_MAINTENANCE)] = this.m_margin_rate.BuyStopLimit.Maintenance;
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_MARGIN_SHORT_INITIAL)]             = this.m_margin_rate.Short.Initial;
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_MARGIN_SELL_STOP_INITIAL)]         = this.m_margin_rate.SellStop.Initial;
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_MARGIN_SELL_LIMIT_INITIAL)]        = this.m_margin_rate.SellLimit.Initial;
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_MARGIN_SELL_STOPLIMIT_INITIAL)]    = this.m_margin_rate.SellStopLimit.Initial;
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_MARGIN_SHORT_MAINTENANCE)]         = this.m_margin_rate.Short.Maintenance;
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_MARGIN_SELL_STOP_MAINTENANCE)]     = this.m_margin_rate.SellStop.Maintenance;
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_MARGIN_SELL_LIMIT_MAINTENANCE)]    = this.m_margin_rate.SellLimit.Maintenance;
   this.m_double_prop[this.IndexProp(SYMBOL_PROP_MARGIN_SELL_STOPLIMIT_MAINTENANCE)]= this.m_margin_rate.SellStopLimit.Maintenance;
   
//--- Fill in the symbol current data
   for(int i=0;i<SYMBOL_PROP_INTEGER_TOTAL;i++)
      this.m_long_prop_event[i][3]=this.m_long_prop[i];
   for(int i=0;i<SYMBOL_PROP_DOUBLE_TOTAL;i++)
      this.m_double_prop_event[i][3]=this.m_double_prop[i];
   
//--- Update the base object data and search for changes
   CBaseObjExt::Refresh();
   this.CheckEvents();
  }
//+------------------------------------------------------------------+

Estas son todas las modificaciones en la clase del objeto de símbolo para que podamos trabajar con la suscripción al DOM en los siguientes artículos.

Prueba

Para la simulación, vamos a tomar el asesor del artículo anterior y guardarlo en la nueva carpeta \MQL5\Experts\TestDoEasy\Part62\ con el nombre nuevo TestDoEasyPart62.mq5.

Durante la prueba, vamos a seleccionar el trabajo sólo con los símbolos especificados en los ajustes (dos símbolos). Vamos a añadir el parámetro que especifica la bandera del uso de la suscripción a los DOMs para todos los símbolos seleccionados para el trabajo, y veremos cómo se activa la suscripción a los DOMs, cómo se actualizan los datos de la serie de tick, y cómo se añaden nuevos objetos de datos de tick y se controla el tamaño de sus listas de acuerdo con su cantidad máxima establecida.

En el área de los parámetros de entrada, añadimos un parámetro nuevo para poder seleccionar la necesidad de la suscripción a los DOMs para los símbolos seleccionados del EA:

//--- input variables
input    ushort            InpMagic             =  123;  // Magic number
input    double            InpLots              =  0.1;  // Lots
input    uint              InpStopLoss          =  150;  // StopLoss in points
input    uint              InpTakeProfit        =  150;  // TakeProfit in points
input    uint              InpDistance          =  50;   // Pending orders distance (points)
input    uint              InpDistanceSL        =  50;   // StopLimit orders distance (points)
input    uint              InpDistancePReq      =  50;   // Distance for Pending Request's activate (points)
input    uint              InpBarsDelayPReq     =  5;    // Bars delay for Pending Request's activate (current timeframe)
input    uint              InpSlippage          =  5;    // Slippage in points
input    uint              InpSpreadMultiplier  =  1;    // Spread multiplier for adjusting stop-orders by StopLevel
input    uchar             InpTotalAttempts     =  5;    // Number of trading attempts
sinput   double            InpWithdrawal        =  10;   // Withdrawal funds (in tester)
sinput   uint              InpButtShiftX        =  0;    // Buttons X shift 
sinput   uint              InpButtShiftY        =  10;   // Buttons Y shift 
input    uint              InpTrailingStop      =  50;   // Trailing Stop (points)
input    uint              InpTrailingStep      =  20;   // Trailing Step (points)
input    uint              InpTrailingStart     =  0;    // Trailing Start (points)
input    uint              InpStopLossModify    =  20;   // StopLoss for modification (points)
input    uint              InpTakeProfitModify  =  60;   // TakeProfit for modification (points)
sinput   ENUM_SYMBOLS_MODE InpModeUsedSymbols   =  SYMBOLS_MODE_CURRENT;            // Mode of used symbols list
sinput   string            InpUsedSymbols       =  "EURUSD,AUDUSD,EURAUD,EURCAD,EURGBP,EURJPY,EURUSD,GBPUSD,NZDUSD,USDCAD,USDJPY";  // List of used symbols (comma - separator)
sinput   ENUM_INPUT_YES_NO InpUseBook           =  INPUT_YES;                       // Use Depth of Market
sinput   ENUM_TIMEFRAMES_MODE InpModeUsedTFs    =  TIMEFRAMES_MODE_LIST;            // Mode of used timeframes list
sinput   string            InpUsedTFs           =  "M1,M5,M15,M30,H1,H4,D1,W1,MN1"; // List of used timeframes (comma - separator)
sinput   bool              InpUseSounds         =  true; // Use sounds

En la función de la inicialización de la biblioteca OnInitDoEasy(), a saber, en el área para establecer los valores de referencia para los símbolos, añadimos un bloque del código para la suscripción al DOM para cada uno de los símbolos de trabajo. Además, implementaremos la visualización de todas las propiedades del símbolo actual en el diario, para ver que la propiedad nueva del símbolo que hemos añadido hoy funciona de forma correcta.

//+------------------------------------------------------------------+
//| Initializing DoEasy library                                      |
//+------------------------------------------------------------------+
void OnInitDoEasy()
  {
//--- Check if working with the full list is selected
   used_symbols_mode=InpModeUsedSymbols;
   if((ENUM_SYMBOLS_MODE)used_symbols_mode==SYMBOLS_MODE_ALL)
     {
      int total=SymbolsTotal(false);
      string ru_n="\nКоличество символов на сервере "+(string)total+".\nМаксимальное количество: "+(string)SYMBOLS_COMMON_TOTAL+" символов.";
      string en_n="\nNumber of symbols on server "+(string)total+".\nMaximum number: "+(string)SYMBOLS_COMMON_TOTAL+" symbols.";
      string caption=TextByLanguage("Внимание!","Attention!");
      string ru="Выбран режим работы с полным списком.\nВ этом режиме первичная подготовка списков коллекций символов и таймсерий может занять длительное время."+ru_n+"\nПродолжить?\n\"Нет\" - работа с текущим символом \""+Symbol()+"\"";
      string en="Full list mode selected.\nIn this mode, the initial preparation of lists of symbol collections and timeseries can take a long time."+en_n+"\nContinue?\n\"No\" - working with the current symbol \""+Symbol()+"\"";
      string message=TextByLanguage(ru,en);
      int flags=(MB_YESNO | MB_ICONWARNING | MB_DEFBUTTON2);
      int mb_res=MessageBox(message,caption,flags);
      switch(mb_res)
        {
         case IDNO : 
           used_symbols_mode=SYMBOLS_MODE_CURRENT; 
           break;
         default:
           break;
        }
     }
//--- Set the counter start point to measure the approximate library initialization time
   ulong begin=GetTickCount();
   Print(TextByLanguage("--- Инициализация библиотеки \"DoEasy\" ---","--- Initializing the \"DoEasy\" library ---"));
//--- Fill in the array of used symbols
   CreateUsedSymbolsArray((ENUM_SYMBOLS_MODE)used_symbols_mode,InpUsedSymbols,array_used_symbols);
//--- Set the type of the used symbol list in the symbol collection and fill in the list of symbol timeseries
   engine.SetUsedSymbols(array_used_symbols);
//--- Displaying the selected mode of working with the symbol object collection in the journal
   string num=
     (
      used_symbols_mode==SYMBOLS_MODE_CURRENT ? ": \""+Symbol()+"\"" : 
      TextByLanguage(". Количество используемых символов: ",". The number of symbols used: ")+(string)engine.GetSymbolsCollectionTotal()
     );
   Print(engine.ModeSymbolsListDescription(),num);
//--- Implement displaying the list of used symbols only for MQL5 - MQL4 has no ArrayPrint() function
#ifdef __MQL5__
   if(InpModeUsedSymbols!=SYMBOLS_MODE_CURRENT)
     {
      string array_symbols[];
      CArrayObj* list_symbols=engine.GetListAllUsedSymbols();
      for(int i=0;i<list_symbols.Total();i++)
        {
         CSymbol *symbol=list_symbols.At(i);
         if(symbol==NULL)
            continue;
         ArrayResize(array_symbols,ArraySize(array_symbols)+1,SYMBOLS_COMMON_TOTAL);
         array_symbols[ArraySize(array_symbols)-1]=symbol.Name();
        }
      ArrayPrint(array_symbols);
     }
#endif   
//--- Set used timeframes
   CreateUsedTimeframesArray(InpModeUsedTFs,InpUsedTFs,array_used_periods);
//--- Display the selected mode of working with the timeseries object collection
   string mode=
     (
      InpModeUsedTFs==TIMEFRAMES_MODE_CURRENT   ? 
         TextByLanguage("Работа только с текущим таймфреймом: ","Work only with the current Period: ")+TimeframeDescription((ENUM_TIMEFRAMES)Period())   :
      InpModeUsedTFs==TIMEFRAMES_MODE_LIST      ? 
         TextByLanguage("Работа с заданным списком таймфреймов:","Work with a predefined list of Periods:")                                              :
      TextByLanguage("Работа с полным списком таймфреймов:","Work with the full list of all Periods:")
     );
   Print(mode);
//--- Implement displaying the list of used timeframes only for MQL5 - MQL4 has no ArrayPrint() function
#ifdef __MQL5__
   if(InpModeUsedTFs!=TIMEFRAMES_MODE_CURRENT)
      ArrayPrint(array_used_periods);
#endif 
//--- Create timeseries of all used symbols
   engine.SeriesCreateAll(array_used_periods);

//--- Check created timeseries - display descriptions of all created timeseries in the journal
//--- (true - only created ones, false - created and declared ones)
   engine.GetTimeSeriesCollection().PrintShort(false); // Short descriptions
   //engine.GetTimeSeriesCollection().Print(true);      // Full descriptions

//--- Create tick series of all used symbols
   engine.GetTickSeriesCollection().CreateTickSeriesAll();
//--- Check created tick series - display descriptions of all created tick series in the journal
   engine.GetTickSeriesCollection().Print();

//--- Create resource text files
   engine.CreateFile(FILE_TYPE_WAV,"sound_array_coin_01",TextByLanguage("Звук упавшей монетки 1","Falling coin 1"),sound_array_coin_01);
   engine.CreateFile(FILE_TYPE_WAV,"sound_array_coin_02",TextByLanguage("Звук упавших монеток","Falling coins"),sound_array_coin_02);
   engine.CreateFile(FILE_TYPE_WAV,"sound_array_coin_03",TextByLanguage("Звук монеток","Coins"),sound_array_coin_03);
   engine.CreateFile(FILE_TYPE_WAV,"sound_array_coin_04",TextByLanguage("Звук упавшей монетки 2","Falling coin 2"),sound_array_coin_04);
   engine.CreateFile(FILE_TYPE_WAV,"sound_array_click_01",TextByLanguage("Звук щелчка по кнопке 1","Button click 1"),sound_array_click_01);
   engine.CreateFile(FILE_TYPE_WAV,"sound_array_click_02",TextByLanguage("Звук щелчка по кнопке 2","Button click 2"),sound_array_click_02);
   engine.CreateFile(FILE_TYPE_WAV,"sound_array_click_03",TextByLanguage("Звук щелчка по кнопке 3","Button click 3"),sound_array_click_03);
   engine.CreateFile(FILE_TYPE_WAV,"sound_array_cash_machine_01",TextByLanguage("Звук кассового аппарата","Cash machine"),sound_array_cash_machine_01);
   engine.CreateFile(FILE_TYPE_BMP,"img_array_spot_green",TextByLanguage("Изображение \"Зелёный светодиод\"","Image \"Green Spot lamp\""),img_array_spot_green);
   engine.CreateFile(FILE_TYPE_BMP,"img_array_spot_red",TextByLanguage("Изображение \"Красный светодиод\"","Image \"Red Spot lamp\""),img_array_spot_red);

//--- Pass all existing collections to the main library class
   engine.CollectionOnInit();

//--- Set the default magic number for all used symbols
   engine.TradingSetMagic(engine.SetCompositeMagicNumber(magic_number));
//--- Set synchronous passing of orders for all used symbols
   engine.TradingSetAsyncMode(false);
//--- Set the number of trading attempts in case of an error
   engine.TradingSetTotalTry(InpTotalAttempts);
//--- Set correct order expiration and filling types to all trading objects
   engine.TradingSetCorrectTypeExpiration();
   engine.TradingSetCorrectTypeFilling();

//--- Set standard sounds for trading objects of all used symbols
   engine.SetSoundsStandart();
//--- Set the general flag of using sounds
   engine.SetUseSounds(InpUseSounds);
//--- Set the spread multiplier for symbol trading objects in the symbol collection
   engine.SetSpreadMultiplier(InpSpreadMultiplier);
      
//--- Set controlled values for symbols
   //--- Get the list of all collection symbols
   CArrayObj *list=engine.GetListAllUsedSymbols();
   if(list!=NULL && list.Total()!=0)
     {
      //--- In a loop by the list, set the necessary values for tracked symbol properties
      //--- By default, the LONG_MAX value is set to all properties, which means "Do not track this property" 
      //--- It can be enabled or disabled (by setting the value less than LONG_MAX or vice versa - set the LONG_MAX value) at any time and anywhere in the program

      for(int i=0;i<list.Total();i++)
        {
         CSymbol* symbol=list.At(i);
         if(symbol==NULL)
            continue;
         if(InpUseBook)
            symbol.BookAdd();
         if(symbol.Name()==Symbol())
            symbol.Print();
         /*
         //--- Set control of the symbol price increase by 100 points
         symbol.SetControlBidInc(100000*symbol.Point());
         //--- Set control of the symbol price decrease by 100 points
         symbol.SetControlBidDec(100000*symbol.Point());
         //--- Set control of the symbol spread increase by 40 points
         symbol.SetControlSpreadInc(400);
         //--- Set control of the symbol spread decrease by 40 points
         symbol.SetControlSpreadDec(400);
         //--- Set control of the current spread by the value of 40 points
         symbol.SetControlSpreadLevel(400);
         */
        }

     }
//--- Set controlled values for the current account
   CAccount* account=engine.GetAccountCurrent();
   if(account!=NULL)
     {
      //--- Set control of the profit increase to 10
      account.SetControlledValueINC(ACCOUNT_PROP_PROFIT,10.0);
      //--- Set control of the funds increase to 15
      account.SetControlledValueINC(ACCOUNT_PROP_EQUITY,15.0);
      //--- Set profit control level to 20
      account.SetControlledValueLEVEL(ACCOUNT_PROP_PROFIT,20.0);
     }
     
//--- Get the end of the library initialization time counting and display it in the journal
   ulong end=GetTickCount();
   Print(TextByLanguage("Время инициализации библиотеки: ","Library initialization time: "),TimeMSCtoString(end-begin,TIME_MINUTES|TIME_SECONDS));
  }
//+------------------------------------------------------------------+

Vamos a compilar e iniciar el asesor en el gráfico del símbolo EURUSD, seleccionando previamente en los ajustes el uso de dos símbolos de la lista (EURUSD y AUDUSD), y la necesidad de suscribirse a los DOMs para todos los símbolos seleccionados:

Después de ejecutar el EA, en el diario se mostrarán mensajes sobre la suscripción activada a los DOMs de dos símbolos. Luego, se mostrarán todas las propiedades del símbolo EURUSD, donde va a figurar la cadena de la propiedad nueva sobre el estado de la suscripción al DOM:

Account 8550475: Artyom Trishkin (MetaQuotes Software Corp.) 10426.13 USD, 1:100, Hedge, MetaTrader 5 demo
--- Initializing "DoEasy" library ---
Working with predefined symbol list. The number of used symbols: 2
"AUDUSD" "EURUSD"
Working with the current timeframe only: H1
AUDUSD symbol timeseries: 
- Timeseries "AUDUSD" H1: Requested: 1000, Actual: 1000, Created: 1000, On the server: 6325
EURUSD symbol timeseries: 
- Timeseries "EURUSD" H1: Requested: 1000, Actual: 1000, Created: 1000, On the server: 5806
Tick series "AUDUSD": Requested number of days: 1, Historical data created: 183398
Tick series "EURUSD": Requested number of days: 1, Historical data created: 148089
Subscribed to Depth of Market  AUDUSD
Subscribed to Depth of Market  EURUSD
============= Beginning of parameter list: "EURUSD" (Euro vs US Dollar) ==================
Status: Major Forex symbol
Index in Market Watch: 2
Custom symbol: No
Price type used for generating bars: Bars are built based on Bid prices
Symbol selected in Market Watch: Yes
Symbol visible in Market Watch: Yes
Number of deals in the current session: 0
Total number of Buy orders at the moment: 0
Total number of Sell orders at the moment: 0
Volume of the last deal: 0
Maximal day volume: 0
Minimal day volume: 0
Time of the last quote: 2021.01.26 22:41:04.852
Number of decimal places: 5
Digits after a decimal point in the value of the lot: 2
Spread value in points: 2
Floating spread: Yes
Maximum number of requests displayed in DOM: 10
Subscription to DOM: Yes
Contract price calculation mode: Forex mode
Order execution type: No trading limitations
Trading start date for an instrument: (No)
Trading end date for an instrument: (No)
Minimal indention from the close price to place Stop orders: 0
Freeze distance for trading operations: 0
Deal execution mode: Instant execution
Swap calculation model: Swaps charged in points
Triple-day swap: Wednesday
Calculating hedging margin using the larger leg: No
Flags of allowed order expiration modes: 
 - Unlimited (Yes)
 - Valid till the end of the day (Yes)
 - Time is specified in the order (Yes)
 - Date specified in order (Yes)
Flags of allowed order filling modes: 
 - Return (Yes)
 - Fill or Kill (Yes)
 - Immediate or Cancel order (No)
Flags of allowed order types: 
 - Market order (Yes)
 - Limit order (Yes)
 - Stop order (Yes)
 - Stop limit order (Yes)
 - StopLoss (Yes)
 - TakeProfit (Yes)
 - Close by (Yes)
StopLoss and TakeProfit order validity periods: Pending orders and Stop Loss/Take Profit levels valid for unlimited period until their explicit cancellation
Option type: European option may only be exercised on a specified date
Option right: Call option gives you right to buy asset at specified price
Background color of the symbol in Market Watch: (No)
------
Bid price: 1.21665
Highest Bid price of the day: 1.21760
Lowest Bid price of the day: 1.21078
Ask price: 1.21667
Highest Ask price of the day: 1.21760
Lowest Ask price of the day: 1.21081
Real volume of the day: 0.00
Maximum real volume of the day: 0.00
Minimum real volume of the day: 0.00
Option execution price: 0.00000
Point value: 0.00001
Calculated tick value for a position: 1.00
Calculated tick value for a winning position: 1.00
Calculated tick value for a losing position: 1.00
Minimum price change: 0.00001
Trade contract size: 100000.00
Accrued interest: 0.00
Initial bond value set by the issuer: 0.00
Liquidity rate: 0.00
Minimum volume for deal execution: 0.01
Maximum volume for deal execution: 500.00
Minimal volume change step for deal execution: 0.01
Maximum allowed aggregate volume of an open position and pending orders in one direction: 0.00
Long swap value: -0.70
Short swap value: -1.00
Initial margin: 0.00000000
Maintenance margin for an instrument: 0.00000000
Initial margin requirement applicable to long positions: 1.00000000
Initial margin requirement applicable to BuyStop orders: (Value not set)
Initial margin requirement applicable to BuyLimit orders: (Value not set)
Initial margin requirement applicable to BuyStopLimit orders: (Value not set)
Maintenance margin requirement applicable to long positions: (Value not set)
Maintenance margin requirement applicable to BuyStop orders: (Value not set)
Maintenance margin requirement applicable to BuyLimit orders: (Value not set)
Maintenance margin requirement applicable to BuyStopLimit orders: (Value not set)
Initial margin requirement applicable to short positions: 1.00000000
Initial margin requirement applicable to SellStop orders: (Value not set)
Initial margin requirement applicable to SellLimit orders: (Value not set)
Initial margin requirement applicable to SellStopLimit orders: (Value not set)
Maintenance margin requirement applicable to short positions: (Value not set)
Maintenance margin requirement applicable to SellStop orders: (Value not set)
Maintenance margin requirement applicable to SellLimit orders: (Value not set)
Maintenance margin requirement applicable to SellStopLimit orders: (Value not set)
Total volume of deals in the current session: 0.00
Total turnover in the current session: 0.00
Total volume of open positions: 0.00
Total volume of Buy orders at the moment: 0.00
Total volume of Sell orders at the moment: 0.00
Open price of the session: 1.21371
Close price of the session: 1.21413
Average weighted price of the session: 0.00000
Settlement price of the current session: 0.00000
Minimum allowable price value for the session: 0.00000
Maximum allowable price value for the session: 0.00000
Size of a contract or margin for one lot of hedged positions: 100000.00
------
Symbol name: EURUSD
Name of the underlaying asset for a derivative symbol: (No)
Instrument base currency: "EUR"
Profit currency: "USD"
Margin funds currency: "EUR"
Source of the current quote: (No)
Symbol description: "Euro vs US Dollar"
Symbol name in ISIN system: (No)
Address of the web page containing symbol information: "http://www.google.com/finance?q=EURUSD"
Location in the symbol tree: "Forex\EURUSD"
Name of the category or sector the symbol belongs to: (No)
Name of the exchange in which the security is traded: (No)
================== End of parameter list: "EURUSD" (Euro vs US Dollar) ==================
 
Library initialization time: 00:00:09.953

La cadena del método Refresh() de la clase de la serie de tick para el símbolo AUDUSD se mostrará en el comentario en el gráfico: el número de ticks nuevamente copiados, la hora anterior, la hora actual y el número total de datos de tick que aparecen en la lista de la serie de tick:

¿Qué es lo próximo?

En el siguiente artículo, empezaremos a crear la funcionalidad de la biblioteca que nos permitirá trabajar con los DOMs de los símbolos.

Más abajo se adjuntan todos los archivos de la versión actual de la biblioteca y el archivo del asesor de prueba para MQL5. Puede descargarlo todo y ponerlo a prueba por sí mismo.
Si tiene preguntas, observaciones o sugerencias, podrá concretarlas en los comentarios al artículo.

Volver al contenido

*Artículos de esta serie:

Trabajando con las series temporales en la biblioteca DoEasy (Parte 35): El objeto "Barra" y la lista de serie temporal del símbolo
Trabajando con las series temporales en la biblioteca DoEasy (Parte 36): El objeto de series temporales de todos los periodos utilizados del símbolo
Trabajando con las series temporales en la biblioteca DoEasy (Parte 37): Colección de series temporales - Base de datos de series temporales según el símbolo y el periodo
Trabajando con las series temporales en la biblioteca DoEasy (Parte 38): Colección de series temporales - Actualización en tiempo real y acceso a los datos desde el programa
Trabajando con las series temporales en la biblioteca DoEasy (Parte 39): Indicadores basados en la biblioteca - Preparación de datos y eventos de la series temporales
Trabajando con las series temporales en la biblioteca DoEasy (Parte 40): Indicadores basados en la biblioteca - actualización de datos en tiempo real
Trabajando con las series temporales en la biblioteca DoEasy (Parte 41): Ejemplo de indicador de símbolo y periodo múltiples
Trabajando con las series temporales en la biblioteca DoEasy (Parte 42): La clase del objeto de búfer de indicador abstracto
Trabajando con las series temporales en la biblioteca DoEasy (Parte 43): Las clases de los objetos de búferes de indicador
Trabajando con las series temporales en la biblioteca DoEasy (Parte 44): Las clases de colección de los objetos de búferes de indicador
Trabajando con las series temporales en la biblioteca DoEasy (Parte 45): Búferes de indicador de periodo múltiple
Trabajando con las series temporales en la biblioteca DoEasy (Parte 46): Búferes de indicador de periodo y símbolos múltiples
Trabajando con las series temporales en la biblioteca DoEasy (Parte 47): Indicadores estándar de periodo y símbolo múltiples
Trabajando con las series temporales en la biblioteca DoEasy (Parte 48): Indicadores de periodo y símbolo múltiples en un búfer en una subventana
Trabajando con las series temporales en la biblioteca DoEasy (Parte 49): Indicadores estándar de periodo, símbolo y búfer múltiples
Trabajando con las series temporales en la biblioteca DoEasy (Parte 50): Indicadores estándar de periodo y símbolo múltiples con desplazamiento
Trabajando con las series temporales en la biblioteca DoEasy (Parte 51): Indicadores estándar compuestos de período y símbolo múltiples
Trabajando con las series temporales en la biblioteca DoEasy (Parte 52): Concepto multiplataforma de indicadores estándar de periodo y símbolo múltiples de búfer único
Trabajando con las series temporales en la biblioteca DoEasy (Parte 53): Clase del indicador abstracto básico
Trabajando con las series temporales en la biblioteca DoEasy (Parte 54): Clases herederas del indicador abstracto básico
Trabajando con las series temporales en la biblioteca DoEasy (Parte 55): Clase de colección de indicadores
Trabajando con las series temporales en la biblioteca DoEasy (Parte 56): Objeto del indicador personalizado, obtención de datos de parte de los objetos de indicador en la colección
Trabajando con las series temporales en la biblioteca DoEasy (Parte 57): Objeto de datos del búfer de indicador
Trabajando con las series temporales en la biblioteca DoEasy (Parte 58): Series temporales de los datos de búferes de indicadores
Trabajando con los precios en la biblioteca DoEasy (Parte 59): Objeto para almacenar los datos de un tick
Trabajando con los precios en la biblioteca DoEasy (Parte 60): Lista de serie de datos de tick del símbolo
Trabajando con los precios en la biblioteca DoEasy (Parte 61): Colección de series de tick de los símbolos