请问窗体从活动到非活动状态的响应过程是OnDeactivate吗？但我试过没有响应这个过程，不知道是为什么。

系统没有提供这个事件的，不过您可以通过API函数GETACTIVEWINDOW进行判断，非常简单。    以下是通过TIMER控件实现的窗体活动状态监控，您可以移植到需要的地方，不知道对您能否有帮助。    

//GetActiveWindow 活动当前WINDOWS活动窗口
//Self.Handle 本程序窗口的句柄
procedure TForm1.Timer1Timer(Sender: TObject);
begin
  if GetActiveWindow <> Self.Handle then
    Edit1.Text := 'No Active'
  else
    Edit1.Text := 'Active';
end;

Hi cxg,    Form 的 OnDeactive 事件 Delphi 的說明如下：    OnDeactivate event (TCustomForm) Occurs when the form loses focus. Description Use OnDeactivate to perform special processing when the form transitions from being the active form to another form in the same application becoming the active form. If activation goes to another application, this event is not triggered. To determine if another application has become active, Use the TApplication object’s OnDeactivate event. PS:TApplicationEvents 位於 Additional TAB 中 ---------------------------------- 小弟才疏學淺，若有謬誤尚請不吝指教 ----------------------------------

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Fishman