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Bind to parent DataContext within DataTemplate

I'm trying to bind MenuItem's Command to command contained in UserControl.DataContext. I've found couple of similar question, but solution according to them is failing to me:

<UserControl ...>
<UserControl.Resources>
    <DataTemplate x:Key="TileItemStye">
        <Grid Width="100" Height="100">
            <Grid.ContextMenu>
                <ContextMenu>
                    <MenuItem Header="Remove" 
                              Command="{Binding DataContext.RemoveItem, 
                              RelativeSource={RelativeSource FindAncestor,
                                             AncestorType=UserControl}}">
                    </MenuItem>
                </ContextMenu>
            </Grid.ContextMenu>
        </Grid>
    </DataTemplate>
</UserControl.Resources>
<Grid>
    <ListView ItemsSource="{Binding Path=Files}" 
              ItemTemplate="{DynamicResource TileItemStye}"  >
    <ListView.ItemsPanel>
        <ItemsPanelTemplate>
            <WrapPanel />
        </ItemsPanelTemplate>
    </ListView.ItemsPanel>
</ListView>
</Grid>

UserControl's DataContext is ViewModel with ICommand RemoveItem and ObservableCollection<FileViewModel> Files.

like image 383
bkovacic Avatar asked Sep 29 '11 08:09

bkovacic


2 Answers

If you are on .NET 4 there indeed is a more elegant solution:

<UserControl Name="uc" ...>
<!-- ... -->
    <MenuItem Header="Remove"
              Command="{Binding DataContext.RemoveItem,
                                Source={x:Reference uc}}"/>

(This requires that the template stays in the Resources, otherwise there will be a cyclical dependency error)

like image 50
H.B. Avatar answered Oct 26 '22 22:10

H.B.


Menus are not drawn in the same Visual Tree as your Controls, which is why the RelativeSource binding does not work

You need to bind to the PlacementTarget of your ContextMenu to access the main Visual Tree

<MenuItem Header="Remove" 
          Command="{Binding PlacementTarget.DataContext.RemoveItem, 
              RelativeSource={RelativeSource FindAncestor, 
              AncestorType={x:Type ContextMenu}}}" />
like image 4
Rachel Avatar answered Oct 27 '22 00:10

Rachel