Silverlight 3中的SaveFileDialog存在問題

我在Silverlight 3中通過SaveFileDialog發生了奇怪的異常。我真的不知道問題出在哪裏。Silverlight 3中的SaveFileDialog存在問題

我創建了的實例SaveFileDialog in 加載用戶控件事件。下載按鈕被點擊並且dialogResult是true異步文件下載開始。文件下載完成後，方法OpenFile（）被調用。這工作得很好過一次，但第二次我得到異常：

異常消息：

"No file was selected"

詳情：

{System.InvalidOperationException: No file was selected. 
    at System.Windows.Controls.SaveFileDialog.OpenFile() 
    at Spaces.Client.Views.Dialogs.FileDialog.BL_DownloadFileCompleted(Object sender, EventArguments`1 e) 
    at Spaces.Client.BL.Interface.DownloadFileCompletedEventHandler.Invoke(Object sender, EventArguments`1 e) 
    at Spaces.Client.BL.WebService.SpacesService._spacesService_DownloadFileCompleted(Object sender, DownloadFileCompletedEventArgs e) 
    at System.EventHandler`1.Invoke(Object sender, TEventArgs e) 
    at Spaces.Client.BL.SpacesServiceReference.ServiceClient.OnDownloadFileCompleted(Object state)}

堆棧：

at System.Windows.Controls.SaveFileDialog.OpenFile() 
    at Spaces.Client.Views.Dialogs.FileDialog.BL_DownloadFileCompleted(Object sender, EventArguments`1 e) 
    at Spaces.Client.BL.Interface.DownloadFileCompletedEventHandler.Invoke(Object sender, EventArguments`1 e) 
    at Spaces.Client.BL.WebService.SpacesService._spacesService_DownloadFileCompleted(Object sender, DownloadFileCompletedEventArgs e) 
    at System.EventHandler`1.Invoke(Object sender, TEventArgs e) 
    at Spaces.Client.BL.SpacesServiceReference.ServiceClient.OnDownloadFileCompleted(Object state)

下面的代碼片段：

private void _userControlFileDialog_Loaded(object sender, RoutedEventArgs e) 
     { 
      _comboBoxVersions.ItemsSource = _file.Versions; 
      if (_comboBoxVersions.Items.Count > 0) 
       _comboBoxVersions.SelectedIndex = 0; 

      String extension = "*." + _file.Extension; 

      _sfd = new SaveFileDialog(); 
      _sfd.DefaultExt = _file.Extension; 
      _sfd.Filter = extension + "|" + extension; 
     } 

     private void _hyperlinkButtonDownload_Click(object sender, RoutedEventArgs e) 
     { 
      string path = ((FileVersion)_comboBoxVersions.SelectedItem).Url; 

      bool? dialogResult = _sfd.ShowDialog(); 

      if (dialogResult == true) 
      { 
       AppContext.BL.DownloadFileCompleted += new Spaces.Client.BL.Interface.DownloadFileCompletedEventHandler(BL_DownloadFileCompleted); 
       AppContext.BL.DownloadFileAsync(AppContext.AuthenticatedUser, path); 
      } 
     } 

     void BL_DownloadFileCompleted(object sender, Spaces.Client.BL.Interface.EventArguments<byte[]> e) 
     { 
      byte [] data = e._result; 

      using (Stream fileStream = (Stream)_sfd.OpenFile()) 
      { 
       fileStream.Write(data, 0, data.Length); 
       fileStream.Flush(); 
       fileStream.Close(); 
      } 

     }

有任何人知道什麼是錯的？

問候安東Kalcik

來源

2009-10-01 Anton Kalcik

嘗試在usrctrl加載事件一旦綁定DownloadFileCompleted事件，但我懷疑這會解決您的問題，對不起。 – Neil 2009-10-03 05:32:49

你好，沒有你的建議不能解決它:-(。我不知道什麼是錯的。謝謝 – 2009-10-03 08:24:42