Question

I have an ItemsControl whose for the ItemTemplate DataTemplate contains a Button. I want the Command on the button to bind to a Command on the DataContext of the ItemsControl, not the ItemTemplate. I think the solution has to do with using RelativeSource, but my attempts so far have failed:

<ItemsControl ItemsSource="{Binding Games}">        
    <ItemsControl.ItemTemplate>
        <DataTemplate>
            <Button Command="{Binding Path=GameSelectedCommand, Source={RelativeSource FindAncestor, AncestorType={x:Type ItemsControl}}}" 
                    CommandParameter="{Binding}" 
                    Style="{StaticResource MenuButtonStyle}" 
                    Content="{Binding Name}"/>    
        </DataTemplate>
    </ItemsControl.ItemTemplate>
</ItemsControl>

How can I get the Button to bind to the GameSelectedCommand of the ItemsControl’s DataContext object?

Answer 1

You’re setting the source of the binding to the ItemsControl itself. Therefore, you’ll need to dereference the DataContext of the ItemsControl:

Command="{Binding DataContext.GameSelectedCommand, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type ItemsControl}}}"

How would you have known this? Take a look at your debug output window when running the app. You’ll see a message along the lines of “Cannot resolve property ‘GameSelectedCommand’ on type ‘ItemsControl'”.