问如何在Delphi7中捕获TDateTimePicker组件的onmouseleave事件

EN

TDateTimePicker = class(ComCtrls.TDateTimePicker)   
   procedure CMMouseLeave(var Message: TMessage); message CM_MOUSELEAVE;  
 end;

 { TDateTimePicker }

 procedure TDateTimePicker.CMMouseLeave(var Message: TMessage);
 begin 
   {do something}; 
 end;

procedure TForm1.FormCreate(Sender: TObject);
begin
    application.OnMessage := AppMsg;
    // Save the windows hande of the date time picker...
    DTWind := DateTimePicker1.handle;
end;

procedure TForm1.AppMsg(var Msg: TMsg; var Handled: Boolean);
begin
  // If we find a mouse leave event, for the date/time picker,
  // then do something
  if (msg.message = 160) and
     (msg.hwnd = DTWind)
  then
  begin
     if dateTimePicker1.color = clBlue
     then dateTimePicker1.Color := clRed
     else  dateTimePicker1.Color := clBlue;
  end;
end;