假設寫了兩個元件，TCtrl元件和TPanel元件如下： 當TCtrl屬性改變時要如何發出一個訊息通知數個TPanel 我想應該是發訊息才能做到，不過沒寫過，還請先進指點一下，謝謝 TCtrl=calss(Tcomponent) public property width:TColor; property color:TColor; end; Tpanel=class(TCustomControl) public Property Ctrl:TColorCtrl read FColorCtrl write setColorCtrl; end;

const MyMsg=WM_USER 100;
TMyPanel=class(TCustomControl)
private
  procedure DoMyMsg(msg....);message MyMsg;
public
  ....
end;
...
procedure TPanel.SetCtrl(Value:TCtrl)
begin
  if Value<>FCtrl then
  begin
     Perform(MyMsg,0,0);
     FCtrl:=Value;
  end; 
end;
procedure TPanel.DoMyMsg;
begin
  DoSomeThing.....
end;