delphi – 当鼠标离开我的控制时,如何触发事件？

使用TButton的插入器类检查此示例

type
  TButton = class(StdCtrls.TButton)
  private
    FOnMouseLeave: TNotifyEvent;
    procedure CMMouseLeave(var Message: TMessage); message CM_MOUSELEAVE;
  protected
    property OnMouseLeave: TNotifyEvent read FOnMouseLeave write FOnMouseLeave;
  end;


  TForm1 = class(TForm)
    Button1: TButton;
    Edit1: TEdit;
    procedure FormCreate(Sender: TObject);
  private
     procedure ButtonMouseLeave(Sender: TObject);
  public
  end;

//handle the message and call the event handler
procedure TButton.CMMouseLeave(var Message: TMessage);
begin
  if (Message.LParam = 0) and Assigned(FOnMouseLeave) then
      FOnMouseLeave(Self);
end;


procedure TForm1.ButtonMouseLeave(Sender: TObject);
begin
   //your code goes here   
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
  //assign the event
  Button1.OnMouseLeave:=ButtonMouseLeave;
end;