public void End()
 {
     CoreApplication.MainView.CoreWindow.Dispatcher.RunAsync(
         CoreDispatcherPriority.High,
         new DispatchedHandler(() => {
         DownManager.ShowDialog("下载完毕");
         this.text.Text = "";
     })
         );
 }
 public void Start(int len)
 {
     down.len   = len;
     down.index = 0;
     CoreApplication.MainView.CoreWindow.Dispatcher.RunAsync(
         CoreDispatcherPriority.High,
         new DispatchedHandler(() =>
     {
         this.text.Text = 0 + "/" + len;
         DownManager.ShowDialog("开始下载");
     }));
 }