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Types of Chart Events

There are 9 types of events that can be processed using the predefined function OnChartEvent(). For custom events 65535 identifiers are provided in the range of CHARTEVENT_CUSTOM to CHARTEVENT_CUSTOM_LAST inclusive. To generate a custom event, the EventChartCustom() function should be used.

ENUM_CHART_EVENT

ID

Description

CHARTEVENT_KEYDOWN

Keystrokes

CHARTEVENT_MOUSE_MOVE

Mouse move, mouse clicks (if CHART_EVENT_MOUSE_MOVE=true is set for the chart)

CHARTEVENT_OBJECT_CREATE

Graphical object created (if CHART_EVENT_OBJECT_CREATE=true is set for the chart)

CHARTEVENT_OBJECT_CHANGE

Graphical object property changed via the properties dialog

CHARTEVENT_OBJECT_DELETE

Graphical object deleted (if CHART_EVENT_OBJECT_DELETE=true is set for the chart)

CHARTEVENT_CLICK

Clicking on a chart

CHARTEVENT_OBJECT_CLICK

Clicking on a graphical object

CHARTEVENT_OBJECT_DRAG

Drag and drop of a graphical object

CHARTEVENT_OBJECT_ENDEDIT

End of text editing in the graphical object Edit

CHARTEVENT_CHART_CHANGE

Change of the chart size or modification of chart properties through the Properties dialog

CHARTEVENT_CUSTOM

Initial number of an event from a range of custom events

CHARTEVENT_CUSTOM_LAST

The final number of an event from a range of custom events

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 events (if 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 change of the chart size or modification of chart properties through the Properties dialog

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:

#define KEY_NUMPAD_5       12
#define KEY_LEFT           37
#define KEY_UP             38
#define KEY_RIGHT          39
#define KEY_DOWN           40
#define KEY_NUMLOCK_DOWN   98
#define KEY_NUMLOCK_LEFT  100
#define KEY_NUMLOCK_5     101
#define KEY_NUMLOCK_RIGHT 102
#define KEY_NUMLOCK_UP    104
//+------------------------------------------------------------------+
//| Expert initialization function                                   |
//+------------------------------------------------------------------+
int OnInit()
  {
//---
   Print("The expert with name ",MQL5InfoString(MQL5_PROGRAM_NAME)," is running");
//--- enable object create events
   ChartSetInteger(ChartID(),CHART_EVENT_OBJECT_CREATE,true);
//--- enable object delete events
   ChartSetInteger(ChartID(),CHART_EVENT_OBJECT_DELETE,true);
//---
   return(INIT_SUCCEEDED);
  }
//+------------------------------------------------------------------+
//| ChartEvent function                                              |
//+------------------------------------------------------------------+
void OnChartEvent(const int id,         // Event identifier  
                  const long& lparam,   // Event parameter of long type
                  const double& dparam, // Event parameter of double type
                  const string& sparam  // Event parameter of string type
                  )
  {
//--- the left mouse button has been pressed on the chart
   if(id==CHARTEVENT_CLICK)
     {
      Print("The coordinates of the mouse click on the chart are: x = ",lparam,"  y = ",dparam);
     }
//--- the mouse has been clicked on the graphic object
   if(id==CHARTEVENT_OBJECT_CLICK)
     {
      Print("The mouse has been clicked on the object with name '"+sparam+"'");
     }
//--- the key has been pressed
   if(id==CHARTEVENT_KEYDOWN)
     {
      switch(lparam)
        {
         case KEY_NUMLOCK_LEFT:  Print("The KEY_NUMLOCK_LEFT has been pressed");   break;
         case KEY_LEFT:          Print("The KEY_LEFT has been pressed");           break;
         case KEY_NUMLOCK_UP:    Print("The KEY_NUMLOCK_UP has been pressed");     break;
         case KEY_UP:            Print("The KEY_UP has been pressed");             break;
         case KEY_NUMLOCK_RIGHT: Print("The KEY_NUMLOCK_RIGHT has been pressed");  break;
         case KEY_RIGHT:         Print("The KEY_RIGHT has been pressed");          break;
         case KEY_NUMLOCK_DOWN:  Print("The KEY_NUMLOCK_DOWN has been pressed");   break;
         case KEY_DOWN:          Print("The KEY_DOWN has been pressed");           break;
         case KEY_NUMPAD_5:      Print("The KEY_NUMPAD_5 has been pressed");       break;
         case KEY_NUMLOCK_5:     Print("The KEY_NUMLOCK_5 has been pressed");      break;
         default:                Print("Some not listed key has been pressed");
        }
      ChartRedraw();
     }
//--- the object has been deleted
   if(id==CHARTEVENT_OBJECT_DELETE)
     {
      Print("The object with name ",sparam," has been deleted");
     }
//--- the object has been created
   if(id==CHARTEVENT_OBJECT_CREATE)
     {
      Print("The object with name ",sparam," has been created");
     }
//--- the object has been moved or its anchor point coordinates has been changed
   if(id==CHARTEVENT_OBJECT_DRAG)
     {
      Print("The anchor point coordinates of the object with name ",sparam," has been changed");
     }
//--- the text in the Edit of object has been changed
   if(id==CHARTEVENT_OBJECT_ENDEDIT)
     {
      Print("The text in the Edit field of the object with name ",sparam," has been changed");
     }
  }

For CHARTEVENT_MOUSE_MOVE event the sparam string parameter contains information about state of the keyboard and mouse buttons:

Bit

Description

1

State of the left mouse button

2

State of the right mouse button

3

State of the SHIFT button

4

State of the CTRL button

5

State of the middle mouse button

6

State of the first extra mouse button

7

State of the second extra mouse button

Example:

//+------------------------------------------------------------------+
//| Expert initialization function                                   |
//+------------------------------------------------------------------+
void OnInit()
  {
//--- enable CHART_EVENT_MOUSE_MOVE messages
   ChartSetInteger(0,CHART_EVENT_MOUSE_MOVE,1);
  }
//+------------------------------------------------------------------+
//| MouseState                                                       |
//+------------------------------------------------------------------+
string MouseState(uint state)
  {
   string res;
   res+="\nML: "   +(((state& 1)== 1)?"DN":"UP");   // mouse left
   res+="\nMR: "   +(((state& 2)== 2)?"DN":"UP");   // mouse right 
   res+="\nMM: "   +(((state&16)==16)?"DN":"UP");   // mouse middle
   res+="\nMX: "   +(((state&32)==32)?"DN":"UP");   // mouse first X key
   res+="\nMY: "   +(((state&64)==64)?"DN":"UP");   // mouse second X key
   res+="\nSHIFT: "+(((state& 4)== 4)?"DN":"UP");   // shift key
   res+="\nCTRL: " +(((state& 8)== 8)?"DN":"UP");   // control key
   return(res);
  }
//+------------------------------------------------------------------+
//| ChartEvent function                                              |
//+------------------------------------------------------------------+
void OnChartEvent(const int id,const long &lparam,const double &dparam,const string &sparam)
  {
   if(id==CHARTEVENT_MOUSE_MOVE)
      Comment("POINT: ",(int)lparam,",",(int)dparam,"\n",MouseState((uint)sparam));
  }

See also

Event Handling Functions, Working with events


Updated: 2015.12.03