SaveFileDialog是給錯誤「對話框必須爲用戶啓動」

Question

我得到一個錯誤：

Dialog must be user-initiated 

當我從我的Silverlight應用程序了，我用下面的代碼打開SAVEFILE對話框

主按鈕單擊事件：

private void btnSaveAttach_Click(object sender, RoutedEventArgs e) 
     { 
      if (EditableGV.SelectedItems.Count == 1) 
      { 
       PositionAttachment posAtt = new PositionAttachment(); 
       posAtt = (PositionAttachment)EditableGV.SelectedItems[0]; 
       SaveFile(posAtt.File, posAtt.FileName); 

      } 
      else 
      { 
       RadWindow.Alert("Please select a attachment from the existing attachments list.", null); 
       return; 
      } 

     } 

private void SaveFile(byte[] fileByte, string fileName) 
    { 
     try 
     { 
      byte[] fileBytes = fileByte;//your bytes here 

      //Show the dialog   

      SaveFileDialog dialog2 = new SaveFileDialog(); 
      saveDialog = dialog2.ShowDialog();//This line is giving the error 

      if (saveDialog == true) 
      { 
       //Get the file stream 
       dialog2.DefaultFileName = fileName; 
       string fileExt = fileName.Substring(fileName.LastIndexOf('.'), fileName.Length); 
       dialog2.DefaultExt = "All Files|*.*|" + fileExt + "|*." + fileExt + ""; 
       using (Stream fs = (Stream)dialog2.OpenFile()) 
       { 
        fs.Write(fileBytes, 0, fileBytes.Length); 
        fs.Close(); 

        //File successfully saved 
       } 
      } 
     } 
     catch 
     { 
      MessageBox.Show("Error in downloading file"); 
     } 
    } 

XMAL代碼：

<StackPanel x:Name="Layout"> 
    <StackPanel x:Name="Messagepanel" Margin="2" Visibility="Collapsed"> 
     <TextBlock x:Name="txtMessage" Text="1" Height="35"></TextBlock> 
    </StackPanel> 
    <StackPanel Orientation="Horizontal" Margin="4"> 
     <sdk:Label Height="28" Content="Select File:" Name="lblSelectFile" Grid.Column="0" Grid.Row="0" Width="70" /> 
     <TextBox Name="txtFileName" IsReadOnly="True" HorizontalAlignment="Left" VerticalAlignment="Center" Width="303" Grid.Column="1" Margin="12,1,0,0"></TextBox> 
     <Button Content="Browse" Name="btnBrows" Width="55" Height="22" HorizontalAlignment="Left" VerticalAlignment="Center" Margin="16,1,0,0" Click="btnBrows_Click" Grid.Column="1" /> 
    </StackPanel> 
    <StackPanel Orientation="Horizontal" Margin="4"> 
     <sdk:Label Height="28" Content="Description:" Name="lblFileDescription" Grid.Column="0" Grid.Row="1" Width="70" /> 
     <TextBox Height="60" Name="txtComments" Grid.Column="1" 
     VerticalScrollBarVisibility="Auto" Width="301" Margin="13,0,85,2" Grid.Row="1" /> 
    </StackPanel> 
    <StackPanel Orientation="Horizontal" Margin="4"> 

     <Button x:Name="OKButton" Content="Add" Click="OKButton_Click" Width="43" Margin="363,6,10,15" Grid.Row="2" Grid.Column="1" HorizontalAlignment="Left" /> 

     <Button x:Name="CancelButton" Content="Cancel" Click="CancelButton_Click" Width="53" HorizontalAlignment="Right" Margin="0,6,200,15" Grid.Row="2" Grid.Column="1" /> 
    </StackPanel> 
    <StackPanel Orientation="Vertical" Margin="4" Height="224"> 
     <sdk:Label Content="Existing Attachment(s):" Height="20" Margin="15,7,324,10" Name="lblExistingAttachemnt" /> 
     <telerikGrid:RadGridView x:FieldModifier="public" 
         x:Name="EditableGV" 
         AutoGenerateColumns="False" 
         ItemsSource="{Binding PositionAttachemntCollection, Mode=TwoWay}" Margin="0,0,0,7" Height="150"> 
      <telerik:RadGridView.Columns> 
       <telerik:GridViewDataColumn DataMemberBinding="{Binding FileName,Mode=TwoWay}"></telerik:GridViewDataColumn> 
       <telerik:GridViewDataColumn DataMemberBinding="{Binding FileDescription,Mode=TwoWay}"></telerik:GridViewDataColumn> 
       <!--<telerik:GridViewColumn Header="" > 
        <telerik:GridViewColumn.CellTemplate> 
         <DataTemplate> 
          <telerik:RadButton Name="btnDownlaod" Content="Save" Click="HyperlinkButton_Click"></telerik:RadButton> 
          <<HyperlinkButton Click="HyperlinkButton_Click" Content="{Binding FileName,Mode=OneWay}" TargetName="_blank" NavigateUri="http://www.google.com" /> 
         </DataTemplate> 
        </telerik:GridViewColumn.CellTemplate> 
       </telerik:GridViewColumn>--> 
      </telerik:RadGridView.Columns> 
     </telerikGrid:RadGridView> 

     <StackPanel Orientation="Horizontal" Margin="0"> 
      <!--<Button Content="Save Attachment" Name="btnSaveAttach" Width="112" Margin="263,6,10,15" Click="btnSaveAttach_Click" />--> 
      <Button Content="Close" Name="btnClose" Width="75" Margin="3,6,10,15" Click="btnClose_Click" /> 
     </StackPanel> 

    </StackPanel> 
</StackPanel> 

此功能呼籲點擊一個按鈕。我想知道，我也有一個openFiledialog也在同一頁面，但成功打開對話框沒有任何錯誤。爲什麼該savefile對話框導致錯誤。

下面是錯誤的堆棧跟蹤：

at System.Windows.Controls.SaveFileDialog.ShowDialogInternal(Window owner) 
    at System.Windows.Controls.SaveFileDialog.ShowDialog() 
    at IPVWorkbench.Views.AddPositionAttachments.btnSaveAttach_Click(Object sender, RoutedEventArgs e) 
    at System.Windows.Controls.Primitives.ButtonBase.OnClick() 
    at System.Windows.Controls.Button.OnClick() 
    at System.Windows.Controls.Primitives.ButtonBase.OnMouseLeftButtonUp(MouseButtonEventArgs e) 
    at System.Windows.Controls.Control.OnMouseLeftButtonUp(Control ctrl, EventArgs e) 
    at MS.Internal.JoltHelper.FireEvent(IntPtr unmanagedObj, IntPtr unmanagedObjArgs, Int32 argsTypeIndex, Int32 actualArgsTypeIndex, String eventName, UInt32 flags) 

Answer 1

我已經找到了解決方法這一點。我在按鈕單擊時顯示一個確認框，並在確認框的「確定」事件中打開保存文件對話框，這樣它就不會拋出任何異常。

Answer 2

你需要證明你的btnSaveAttach_Click的SaveFileDialog（這樣，它是用戶啓動）。也remove all your breakpoints，因爲他們也可以產生該錯誤。

試試這個，看看它是否工作，然後你建立你的代碼的基礎上它的其餘部分：

private void btnSaveAttach_Click(object sender, RoutedEventArgs e) 
{ 
    SaveFileDialog dialog2 = new SaveFileDialog(); 
    saveDialog = dialog2.ShowDialog(); 
} 

Answer 3

答案就在這裏給出：http://social.msdn.microsoft.com/Forums/en-US/lightswitch/thread/8c6529ab-8967-45e8-9e19-920589b060c1

這是有點「安全功能」：

基本上，你必須直接響應由用戶操作引起的事件打開一個SaveFileDialog或打開文件對話框（例如Click），這些只在主線程中引發。