学习 Message(6): 也可以直接覆盖祖先类的 WndProc 或 Dispatch 方法来响应消息

覆盖: WndProc

---

unit Unit1;



interface



uses

  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,

  Dialogs;



type

  TForm1 = class(TForm)

  protected

    procedure WndProc(var Message: TMessage); override;

  end;



var

  Form1: TForm1;



implementation



{$R *.dfm}



procedure TForm1.WndProc(var Message: TMessage);

begin

  inherited;

  if Message.Msg = WM_LBUTTONDOWN then

    ShowMessage('WndProc');

end;



end.


 
   

覆盖: Dispatch

---

unit Unit1;



interface



uses

  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,

  Dialogs;



type

  TForm1 = class(TForm)

  public

    procedure Dispatch(var Message); override;

  end;



var

  Form1: TForm1;



implementation



{$R *.dfm}



procedure TForm1.Dispatch(var Message);

begin

  inherited;

  if TMessage(Message).Msg = WM_LBUTTONDOWN then

    ShowMessage('Dispatch');

end;



end.