WPF上下文菜单不会绑定到VIewModel属性

Question

I am having a WPF binding issue that I cannot figure out. I have a ContextMenu template that is formatted as shown:

<ContextMenu x:Key="CopyPasteContextMenu">
    <MenuItem Header="AlternateDelete"
              Command="{Binding Path=PlacementTarget.Tag.DataContext.AlternateDeleteCommand, 
              RelativeSource={RelativeSource Self}, Mode=OneWay}"/>
</ContextMenu>

The context menu is being used in the DataTemplat, and the binding for the Tag on the Border is finding the PropertyEditorView correctly, I just can't get it from the border to the contextmenu.

<DataTemplate x:Key="PropertyValueCellViewingTemplate" DataType="viewModels:IConfigurationItemViewModel">
    <Border x:Name="ValueCellBorder"
           Tag="{Binding RelativeSource={RelativeSource AncestorType={x:Type views:PropertyEditorView}}}"
           ContextMenu="{StaticResource CopyPasteContextMenu}"
           Style="{StaticResource PropertyGridValueCellBorderStyle}">
        (...)
    </Border>
</DataTemplate>

The tag can bind properly to my view model which is called “PropertyEditorViewModel”. I can see this while debugging the system in the visual tree. When I drill into my Context Menu, the binding is not happening properly.

For my Command to work, I need it to bind properly to the Command to PropertyEditorView view model command called “AlternateDeleteCommand”.

public class PropertyEditorViewModel : DisposableViewModelBase, IPropertyEditorViewModel
{
    public ICommand AlternateDeleteCommand { get; set; }

Looked at this for a day so far, and not sure why my binding isn't working on the context menu, anyone got something I'm missing?

Thanks!

Answer 1

Doesn't the relative source need to be on the context menu and not on the menu item? Since you are checking the placement target of the context menu?

<MenuItem Header="AlternateDelete"
          Command="{Binding Path=PlacementTarget.Tag.DataContext.AlternateDeleteCommand, 
          RelativeSource={RelativeSource AncestorType={x:Type ContextMenu}}, Mode=OneWay}" />