MQL4 Reference Working with Events EventChartCustom

EventChartCustom

The function generates a custom event for the specified chart.

bool  EventChartCustom(
   long    chart_id,            // identifier of the event receiving chart
   ushort  custom_event_id,     // event identifier
   long    lparam,              // parameter of type long
   double  dparam,              // parameter of type double
   string  sparam               // string parameter of the event
   );

Parameters

chart_id

[in] Chart identifier. 0 means the current chart.

custom_event_id

[in] ID of the user events. This identifier is automatically added to the value CHARTEVENT_CUSTOM and converted to the integer type.

lparam

[in] Event parameter of the long type passed to the OnChartEvent function.

dparam

[in] Event parameter of the double type passed to the OnChartEvent function.

sparam

[in] Event parameter of the string type passed to the OnChartEvent function. If the string is longer than 63 characters, it is truncated.

Return Value

Returns true if a custom event has been successfully placed in the events queue of the chart that receives the events. In case of failure, it returns false. Use GetLastError() to get an error code.

Note

An Expert Advisor or indicator attached to the specified chart handles the event using the function OnChartEvent(int event_id, long& lparam, double& dparam, string& sparam).

For each type of event, the input parameters of the OnChartEvent() function have definite values that are required for the processing of this event. The events and values passed through this parameters are listed in the below table.

Event	Value of the id parameter	Value of the lparam parameter	Value of the dparam parameter	Value of the sparam parameter
Event of a keystroke	CHARTEVENT_KEYDOWN	code of a pressed key	Repeat count (the number of times the keystroke is repeated as a result of the user holding down the key)	The string value of a bit mask describing the status of keyboard buttons
Mouse event (if property CHART_EVENT_MOUSE_MOVE=true is set for the chart)	CHARTEVENT_MOUSE_MOVE	the X coordinate	the Y coordinate	The string value of a bit mask describing the status of mouse buttons
Event of graphical object creation (if CHART_EVENT_OBJECT_CREATE=true is set for the chart)	CHARTEVENT_OBJECT_CREATE			Name of the created graphical object
Event of change of an object property via the properties dialog	CHARTEVENT_OBJECT_CHANGE			Name of the modified graphical object
Event of graphical object deletion (if CHART_EVENT_OBJECT_DELETE=true is set for the chart)	CHARTEVENT_OBJECT_DELETE			Name of the deleted graphical object
Event of a mouse click on the chart	CHARTEVENT_CLICK	the X coordinate	the Y coordinate
Event of a mouse click in a graphical object belonging to the chart	CHARTEVENT_OBJECT_CLICK	the X coordinate	the Y coordinate	Name of the graphical object, on which the event occurred
Event of a graphical object dragging using the mouse	CHARTEVENT_OBJECT_DRAG			Name of the moved graphical object
Event of the finished text editing in the entry box of the LabelEdit graphical object	CHARTEVENT_OBJECT_ENDEDIT			Name of the LabelEdit graphical object, in which text editing has completed
Event of changes on a chart	CHARTEVENT_CHART_CHANGE
ID of the user event under the N number	CHARTEVENT_CUSTOM+N	Value set by the EventChartCustom() function	Value set by the EventChartCustom() function	Value set by the EventChartCustom() function

Example:

//+------------------------------------------------------------------+
//|                                            ButtonClickExpert.mq5 |
//|                        Copyright 2009, MetaQuotes Software Corp. |
//|                                              https://www.mql5.com |
//+------------------------------------------------------------------+
#property copyright "2009, MetaQuotes Software Corp."
#property link      "https://www.mql5.com"
#property version   "1.00"

string buttonID="Button";
string labelID="Info";
int broadcastEventID=5000;
//+------------------------------------------------------------------+
//| Expert initialization function                                   |
//+------------------------------------------------------------------+
int OnInit()
  {
//--- Create a button to send custom events
   ObjectCreate(0,buttonID,OBJ_BUTTON,0,100,100);
   ObjectSetInteger(0,buttonID,OBJPROP_COLOR,clrWhite);
   ObjectSetInteger(0,buttonID,OBJPROP_BGCOLOR,clrGray);
   ObjectSetInteger(0,buttonID,OBJPROP_XDISTANCE,100);
   ObjectSetInteger(0,buttonID,OBJPROP_YDISTANCE,100);
   ObjectSetInteger(0,buttonID,OBJPROP_XSIZE,200);
   ObjectSetInteger(0,buttonID,OBJPROP_YSIZE,50);
   ObjectSetString(0,buttonID,OBJPROP_FONT,"Arial");
   ObjectSetString(0,buttonID,OBJPROP_TEXT,"Button");
   ObjectSetInteger(0,buttonID,OBJPROP_FONTSIZE,10);
   ObjectSetInteger(0,buttonID,OBJPROP_SELECTABLE,0);

//--- Create a label for displaying information
   ObjectCreate(0,labelID,OBJ_LABEL,0,100,100);
   ObjectSetInteger(0,labelID,OBJPROP_COLOR,clrRed);
   ObjectSetInteger(0,labelID,OBJPROP_XDISTANCE,100);
   ObjectSetInteger(0,labelID,OBJPROP_YDISTANCE,50);
   ObjectSetString(0,labelID,OBJPROP_FONT,"Trebuchet MS");
   ObjectSetString(0,labelID,OBJPROP_TEXT,"No information");
   ObjectSetInteger(0,labelID,OBJPROP_FONTSIZE,20);
   ObjectSetInteger(0,labelID,OBJPROP_SELECTABLE,0);

//---
   return(INIT_SUCCEEDED);
  }
//+------------------------------------------------------------------+
//| Expert deinitialization function                                 |
//+------------------------------------------------------------------+
void OnDeinit(const int reason)
  {
//---
   ObjectDelete(0,buttonID);
   ObjectDelete(0,labelID);
  }
//+------------------------------------------------------------------+
//| Expert tick function                                             |
//+------------------------------------------------------------------+
void OnTick()
  {
//---

  }
//+------------------------------------------------------------------+
void OnChartEvent(const int id,
                  const long &lparam,
                  const double &dparam,
                  const string &sparam)
  {
//--- Check the event by pressing a mouse button
   if(id==CHARTEVENT_OBJECT_CLICK)
     {
      string clickedChartObject=sparam;
      //--- If you click on the object with the name buttonID
      if(clickedChartObject==buttonID)
        {
         //--- State of the button - pressed or not
         bool selected=ObjectGetInteger(0,buttonID,OBJPROP_STATE);
         //--- log a debug message
         Print("Button pressed = ",selected);
         int customEventID; // Number of the custom event to send
         string message;    // Message to be sent in the event
         //--- If the button is pressed
         if(selected)
           {
            message="Button pressed";
            customEventID=CHARTEVENT_CUSTOM+1;
           }
         else // Button is not pressed
           {
            message="Button in not pressed";
            customEventID=CHARTEVENT_CUSTOM+999;
           }
         //--- Send a custom event "our" chart
         EventChartCustom(0,customEventID-CHARTEVENT_CUSTOM,0,0,message);
         ///--- Send a message to all open charts
         BroadcastEvent(ChartID(),0,"Broadcast Message");
         //--- Debug message
         Print("Sent an event with ID = ",customEventID);
        }
      ChartRedraw();// Forced redraw all chart objects
     }

//--- Check the event belongs to the user events
   if(id>CHARTEVENT_CUSTOM)
     {
      if(id==broadcastEventID)
        {
         Print("Got broadcast message from a chart with id = "+lparam);
        }
      else
        {
         //--- We read a text message in the event
         string info=sparam;
         Print("Handle the user event with the ID = ",id);
         //--- Display a message in a label
         ObjectSetString(0,labelID,OBJPROP_TEXT,sparam);
         ChartRedraw();// Forced redraw all chart objects
        }
     }
  }
//+------------------------------------------------------------------+
//| sends broadcast event to all open charts                         |
//+------------------------------------------------------------------+
void BroadcastEvent(long lparam,double dparam,string sparam)
  {
   int eventID=broadcastEventID-CHARTEVENT_CUSTOM;
   long currChart=ChartFirst();
   int i=0;
   while(i<CHARTS_MAX)                 // We have certainly no more than CHARTS_MAX open charts
     {
      EventChartCustom(currChart,eventID,lparam,dparam,sparam);
      currChart=ChartNext(currChart); // We have received a new chart from the previous
      if(currChart==-1) break;        // Reached the end of the charts list
      i++;// Do not forget to increase the counter
     }
  }
//+------------------------------------------------------------------+