Silverlight 3中的SaveFileDialog存在问题

我在Silverlight 3中通过SaveFileDialog发生了奇怪的异常。我真的不知道问题出在哪里。Silverlight 3中的SaveFileDialog存在问题

我创建了的实例SaveFileDialog in 加载用户控件事件。下载按钮被点击并且dialogResult是true异步文件下载开始。文件下载完成后，方法OpenFile（）被调用。这工作得很好过一次，但第二次我得到异常：

异常消息：

"No file was selected"

详情：

{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)}

堆栈：

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)

下面的代码片段：

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(); 
      } 

     }

有任何人知道什么是错的？

问候安东Kalcik

来源

2009-10-01 Anton Kalcik

尝试在usrctrl加载事件一旦绑定DownloadFileCompleted事件，但我怀疑这会解决您的问题，对不起。 – Neil 2009-10-03 05:32:49

你好，没有你的建议不能解决它:-(。我不知道什么是错的。谢谢 – 2009-10-03 08:24:42