Example of Overriding a Message Handler

From RAD Studio
Jump to: navigation, search

Go Up to Overriding the Handler Method


For example, to override a component's handling of the WM_PAINT message, you redeclare the WMPaint method:

 type
   TMyComponent = class(...)
   .
   .
   .
   procedure WMPaint(var Message: TWMPaint); message WM_PAINT;
 end;
 class PACKAGE TMyComponent : public TComponent
 {
 protected:
     void __fastcall WMPaint(TWMPaint& Message);
 BEGIN_MESSAGE_MAP
   MESSAGE_HANDLER(WM_PAINT, TWMPaint, WMPaint)
 END_MESSAGE_MAP(TComponent)
 };