Silverlight在OOB模式Closing事件有时失效的解决方法

突然发现，Silverlight在OOB模式Closing事件有时会失效，特别是弹出窗口和导航时很容易无效。经测试以下代码可用：

1. 在App.xaml.cs 定义一个全局变量：

Window MainWin;

 

2. 在Application_Startup写Closing 代码：

        private void Application_Startup(object sender, StartupEventArgs e)
        {
            MainWin = App.Current.MainWindow;
            MainWin.Closing += (sss, eee) =>
            {
                var result = MessageBox.Show(
                                        "确认退出？",
                                        "确认",
                                        MessageBoxButton.OKCancel);
                if (result != MessageBoxResult.OK)
                    eee.Cancel = true;
            };
        }