獲取父

的文本菜單的DataContext我有一個文本菜單綁定到的CommandBinding：獲取父

<MetroTreeView:MetroTreeView x:Name="tvTagList" Grid.Row="1" Margin="15, 0, 15, 0" SelectedItemChanged="tvTagList_SelectedTagChanged" ItemsSource="{Binding}" VerticalAlignment="Stretch" HorizontalAlignment="Stretch" Background="{x:Null}" BorderBrush="{DynamicResource ExtryzeAccentBrushSecondary}" BorderThickness="2" Foreground="White" 
    VirtualizingStackPanel.IsVirtualizing="True" VirtualizingStackPanel.VirtualizationMode="Standard"> 
<MetroTreeView:MetroTreeView.Resources> 
    <HierarchicalDataTemplate DataType="{x:Type DataBind:TagClass}" ItemsSource="{Binding Children}" > 
     <StackPanel Orientation="Horizontal" HorizontalAlignment="Stretch"> 
      <TextBlock> 
       <Run Text="{Binding TagClassMagic}" /> 
       <Run Foreground="{StaticResource TextBrushSecondary}" Text=" - " /> 
       <Run Foreground="{StaticResource TextBrushSecondary}" Text="{Binding Path=Description, Converter={StaticResource IValueTagDescriptionCleanup}}" /> 
      </TextBlock> 
      <StackPanel.ContextMenu> 
       <ContextMenu> 
        <MenuItem Header="Dump Tag List..." Click="DumpClassTagList" /> 
       </ContextMenu> 
      </StackPanel.ContextMenu> 
     </StackPanel> 
    </HierarchicalDataTemplate> 
    <DataTemplate DataType="{x:Type DataBind:TagEntry}"> 
     <StackPanel Orientation="Horizontal" HorizontalAlignment="Stretch"> 
      <StackPanel.ContextMenu> 
       <ContextMenu> 
        <ContextMenu.CommandBindings> 
         <CommandBinding Command="{x:Static DataBind:HaloMap.CommandTagBookmarking }" 
              CanExecute="CommandTagBookmarking_CanExecute" 
              Executed="CommandTagBookmarking_Executed" 
              /> 
        </ContextMenu.CommandBindings> 
        <MenuItem Header="Bookmark Tag" Foreground="White" Command="{x:Static DataBind:HaloMap.CommandTagBookmarking}" CommandParameter="{Binding}" /> 
       </ContextMenu> 
      </StackPanel.ContextMenu> 
      <TextBlock Text="{Binding TagFileName}" /> 
     </StackPanel> 
    </DataTemplate> 
</MetroTreeView:MetroTreeView.Resources> 
<MetroTreeView:MetroTreeView.ItemContainerStyle> 
    <Style TargetType="{x:Type MetroTreeView:MetroTreeViewItem}" BasedOn="{StaticResource {x:Type MetroTreeView:MetroTreeViewItem}}"> 
     <EventSetter Event="MouseDoubleClick" Handler="tvTagList_ItemDoubleClick" /> 
    </Style> 
</MetroTreeView:MetroTreeView.ItemContainerStyle>

但是當我運行CanExecute命令，每一個嘗試訪問的DataContext總是遇到空：

private void CommandTagBookmarking_CanExecute(object sender, CanExecuteRoutedEventArgs e) 
{ 
    var a = e.Source; 
    var b = ((MenuItem)a).DataContext; 
    var c = ((ContextMenu) ((MenuItem) e.Source).Parent).DataContext; 
}

來源

2013-03-15 Alexander Forbes-Reed

試試這個：

<ContextMenu DataContext="{Binding PlacementTarget, RelativeSource={RelativeSource Self}}">

來源

2013-03-15 20:45:10

不，「變種C =（（文本菜單）（（菜單項）e.Source）.Parent）.DataContext;」仍然返回null。 – 2013-03-15 20:49:19

@AlexReed我建議你使用'Snoop'來檢查正在運行的應用程序，看看差距在哪裏。 – 2013-03-15 20:55:12

Snoop甚至不承認我的應用程序正在運行。 – 2013-03-15 21:25:05

由於ContextMenu不在位於其放置對象的VisualTree中。可以選擇使用PlacementTarget繼承對象的DataContext -

<ContextMenu DataContext="{Binding PlacementTarget.DataContext, 
            RelativeSource={RelativeSource Self}}">

來源

2013-03-16 13:16:25

這也返回null：/ – 2013-03-16 15:57:29

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