Action动态实现菜单是否有效

procedure TMainForm.As1Click(Sender: TObject);      //涂磊 添加20241113 JPEG格式导出
begin
  SavePictureDialog.FileName := ChangeFileExt(SaveDialog.FileName, '.jpg');
  if SavePictureDialog.Execute then
    SimpleGraph.SaveAsJPEG(SavePictureDialog.FileName);
end;

procedure TMainForm.ExportJPGUpdate(Sender: TObject);
begin
 As1.Enabled := (SimpleGraph.Objects.Count > 0);
end;

关联到 菜单 

删除后，菜单又无效