How to Add MouseLeave Event

Khaled Shagrouni, November 1, 2000

Arabic

Be sure to have an open door to leave.

Published in  Delphi3000.com
and in some whwere in Chinees

I don't know what is wrong with mouse leave event that makes Borland not to support it in Delphi controls. Bellow is a small and easy to follow example of how to implement this event in TImage control. Also this example shows how to build a simple Delphi component.

If you are new in Delphi programming please see the following notes:

• The example is a Pascal unit, you have to save it in a file with the same unit name as MyImg.pas . 
• This example can be applied to other controls, so you can replace TImage class with other classes as TLabel or TButton.

unit MyImg;
interface
uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms,
  ExtCtrls;
type
  TMyImage = class(TImage)
  private
    FOnMouseLeave: TNotifyEvent;
    procedure CMMouseLeave(var Message: TMessage); message CM_MOUSELEAVE;
  protected
  public
  published
    property OnMouseLeave: TNotifyEvent read FOnMouseLeave write FOnMouseLeave;
  end;

procedure Register;

implementation

procedure Register;
begin
  RegisterComponents('Samples', [TMyImage]);
end;

procedure TMyImage.CMMouseLeave(var Message: TMessage);
begin
  inherited;
  if Assigned(FOnMouseLeave) then FOnMouseLeave(Self);
end;

end.