WPF: Trigger RoutedCommands implemented in UserControl nested inside a ContentControl

Question

How can I trigger routed commands implemented inside a UserControl which is nested inside a ContentControl?

What I basically have is an outer view (derived from UserControl) which contains:

1) A button which should trigger the command MyCommand: The CommandTarget is obviously wrong here, as it should be the view which is hosted inside the ContentControl, and not the content control itself, as the CommandBinding is added to the CommandBindings collection of InnerView.

<Button Command="{x:Static Commands:MyCommands.MyCommand}" CommandTarget="{Binding ElementName=ViewHost}">
    Trigger Command
</Button>

2) A ContentControl. The Content property is bound to the ViewModel which should be used by the inner view:

<ContentControl x:Name="ViewHost" Content="{Binding InnerViewModel}" />

3) A DataTemplate which defines the type of the inner view:

<UserControl.Resources>
    <ResourceDictionary>
        <DataTemplate DataType="{x:Type ViewModels:InnerViewModel}">
            <Views:InnerView />
        </DataTemplate>
    </ResourceDictionary>
</UserControl.Resources>

InnerView (derived from UserControl) sets a CommandBinding in it's Loaded event:

public partial class InnerView : UserControl
{
    private void InnerViewLoaded(object sender, System.Windows.RoutedEventArgs e)
    {
        view.CommandBindings.Add(new CommandBinding(MyCommands.MyCommand, this.ExecuteMyCommand, this.CanExecuteMyCommand));
    }
}

And of course a class which defines the command:

internal class MyCommands
{
    static MyCommands()
    {
        MyCommand = new RoutedCommand("MyCommand", typeof(MyCommands));
    }

    public static RoutedCommand MyCommand { get; private set; }
}

How can I get this working? The problem is probably that the CommandTarget on the Button is wrong. How can I bind the CommandTarget to the control hosted by the ContentControl?

If I put InnerView directly into OuterView and set the Button's CommandTarget to the InnerView instance, it works:

<Views:InnerView x:Name="InnerViewInstance" />

<Button Command="{x:Static Commands:MyCommands.MyCommand}" CommandTarget="{Binding ElementName=InnerViewInstance}">
    Trigger Command
</Button>

Answer 1

I ran into this issue and learned that I had to register a command type dependency property for each user control within my user control hierarchy.

I learned this my another link on this site.

Answer 2

Try this

<UserControl.Resources>
<ResourceDictionary>
    <Views:InnerView x:Key="innerView"/>
    <DataTemplate DataType="{x:Type ViewModels:InnerViewModel}">
        <ContentControl Content="{StaticResource innerView}" />
    </DataTemplate>
</ResourceDictionary>

<Button Command="{x:Static Commands:MyCommands.MyCommand}" CommandTarget="{StaticResource innerView}">
        Trigger Command
    </Button>

I havent tested it but hope this will help you. though this seems a very complex issue.