Wpf Treeview上下文菜單DataContext

Question

我想設置我的上下文菜單的Datacontext - 但我的代碼不起作用。非常類似的代碼在另一個位置工作，所以如果有人能解釋爲什麼它不起作用，我將不勝感激。

我的Treeview看起來像這樣： 注意：它比較長，但我認爲嵌套結構是問題的一部分，所以我想縮小它。 問題發生在ppChart綁定的第二個「級別」上。

<TreeView x:Name ="Presentation_SlidesWithIndex" Grid.ColumnSpan="1" HorizontalAlignment="stretch" Height="auto" Margin="0,0,3,0" VerticalAlignment="stretch" Width="auto" Tag="{Binding DataContext, ElementName=LayoutRoot}"> 
     <TreeView.ItemContainerStyle> 
      <!--expand Charts when they contain elements--> 
      <Style TargetType="TreeViewItem"> 
       <Setter Property="IsExpanded" Value="{Binding HasCharts}"/> 
      </Style> 
     </TreeView.ItemContainerStyle> 

     <TreeView.Resources> 
      <HierarchicalDataTemplate DataType="{x:Type pp:PPSlide}" ItemsSource="{Binding Charts}"> 
       <StackPanel x:Name="PPSlideElements" Orientation="Horizontal"> 
        <StackPanel.Style> 
         <Style TargetType="{x:Type StackPanel}"> 
          <Style.Triggers> 
           <!--Trigger for Slides with Charts--> 
           <DataTrigger Binding="{Binding Path=HasCharts}" Value="True" > 
            <Setter Property="Background" Value="LightBlue" /> 
           </DataTrigger> 
           <!--Trigger for Slides with NO Charts--> 
           <DataTrigger Binding="{Binding Path=HasCharts}" Value="False" > 
            <Setter Property="Opacity" Value=".5" /> 
           </DataTrigger> 
          </Style.Triggers> 
         </Style> 
        </StackPanel.Style> 
        <TextBlock FontSize="15"> 
         <Run Text="Slide "></Run> 
         <Run Text="{Binding Path=Index}"></Run> 
        </TextBlock> 
        <!--<Image Source="/Images/pptIcon.png" Height="10"></Image>--> 
       </StackPanel> 
      </HierarchicalDataTemplate> 
      <HierarchicalDataTemplate DataType="{x:Type pp:PPChart}" ItemsSource="{Binding ExcelSource}"> 
       <StackPanel x:Name="PpChartElements" Orientation="Horizontal" AllowDrop="True" cal:Message.Attach="[Event Drop] = [Action DropItem($eventArgs,$view)]" Tag="{Binding DataContext, RelativeSource={RelativeSource AncestorType=UserControl}}"> 
        <StackPanel.Style> 
         <Style TargetType="{x:Type StackPanel}"> 
          <Style.Triggers> 
           <!--Trigger for Charts with DataSource set--> 
           <DataTrigger Binding="{Binding Path=HasDataSourceSet}" Value="True" > 
            <Setter Property="Background" Value="LightGreen" /> 
           </DataTrigger> 
           <!--Trigger for Charts with DataSource nit set--> 
           <DataTrigger Binding="{Binding Path=HasDataSourceSet}" Value="False" > 
            <Setter Property="Background" Value="Orange" /> 
           </DataTrigger> 
          </Style.Triggers> 
         </Style> 
        </StackPanel.Style> 
        <Image Source="{Binding ChartType, Converter={StaticResource PowerPointChartTypeConverter}}" Width="19" Height="19" Margin="2,2,4,2"></Image> 
        <TextBlock FontSize="14" Text="{Binding Path=ShapeName}" VerticalAlignment="Center"> 
         <TextBlock.ContextMenu> 
          <ContextMenu cal:Action.TargetWithoutContext="{Binding Path=PlacementTarget.Tag.AddEntityCommand, RelativeSource={RelativeSource AncestorType=ContextMenu}}"> 
           <MenuItem Header="Löse Verknüpfung" cal:Message.Attach="DeleteLink($datacontext)" ToolTip="Löscht einen bestehenden Link zu einer Excel Datei"/> 
          </ContextMenu> 
         </TextBlock.ContextMenu> 
        </TextBlock> 
        <Image Source="{Binding PowerPointWriteStatus, Converter={StaticResource PowerPointWriteStatusConverter}}" Width="19" Height="19" Margin="2,2,4,2" ToolTip="Zeigt erfolg oder misserfolg des Erstellens an"></Image> 
       </StackPanel> 
      </HierarchicalDataTemplate> 
      <HierarchicalDataTemplate DataType="{x:Type pp:PPSourceExcelLink}"> 
       <StackPanel x:Name="PpSourceExcelLinkStackPanel" Orientation="Vertical"> 
        <TextBlock FontSize="14"> 
         <Run Text="Datei: "></Run> 
         <Run Text="{Binding Path=ExcelFileName, Mode=OneWay}"></Run> 
        </TextBlock> 
        <TextBlock FontSize="14"> 
         <Run Text="Tabelle: "></Run> 
         <Run Text="{Binding Path=SourceTableID}"></Run> 
        </TextBlock> 
       </StackPanel> 
      </HierarchicalDataTemplate> 

     </TreeView.Resources> 
    </TreeView> 

Answer 1

我覺得你的問題在於究竟在這行代碼：

cal:Action.TargetWithoutContext="{Binding Path=PlacementTarget.Tag.AddEntityCommand, RelativeSource={RelativeSource AncestorType=ContextMenu}}" 

要解決它，你需要將其更改爲：

cal:Action.TargetWithoutContext="{Binding Path=PlacementTarget.Tag.AddEntityCommand, RelativeSource={RelativeSource Self}}" 

但這本身並不能修復您的問題，因爲操作消息的目標將是沒有設置其標籤屬性的TextBlock。

反正你應該結束了類似下面的代碼：

<TextBlock FontSize="14" Text="{Binding Path=ShapeName}" VerticalAlignment="Center" Tag="{Binding DataContext, RelativeSource={RelativeSource Self}}"> 
    <TextBlock.ContextMenu> 
     <ContextMenu cal:Action.TargetWithoutContext="{Binding RelativeSource={RelativeSource Self},Path=PlacementTarget.Tag}"> 
      <MenuItem Header="Löse Verknüpfung" cal:Message.Attach="DeleteLink($datacontext)" ToolTip="Löscht einen bestehenden Link zu einer Excel Datei" /> 
     </ContextMenu> 
    </TextBlock.ContextMenu> 
</TextBlock> 

我最近回答了similar question，你可以看看更多的細節。

Answer 2

我發現它的工作原理相當好一個解決方案 - 但爲什麼它的工作原理是超越我：

<TextBlock FontSize="14" Text="{Binding Path=ShapeName}" VerticalAlignment="Center" Tag="{Binding DataContext, RelativeSource={AncestorType=TreeView}}"> 
    <TextBlock.ContextMenu> 
     <ContextMenu cal:Action.TargetWithoutContext="{Binding RelativeSource={RelativeSource Self},Path=PlacementTarget.Tag}"> 
      <MenuItem Header="Löse Verknüpfung" cal:Message.Attach="DeleteLink($datacontext)" ToolTip="Löscht einen bestehenden Link zu einer Excel Datei" /> 
     </ContextMenu> 
    </TextBlock.ContextMenu> 
</TextBlock> 

注意Ancestertype TreeView的是如何使用的。我敢打賭，它會走向Visual樹直到找到具有適當DataContect的Treeview。 感謝嗅探器，它做得非常好！