DelegateCommand is not invoked in context menu

Question

I can`t seem to get this right click popup menu to work.

Answer 1

Since learning more and more about C# and WPF if anyone else is looking for an answer regarding this. the answer is simple.

Your going about it the wrong way. If you need to use a "Behaviour" over and over again and your using either a MVVM style code (or you think you are because its probably not quite there yet) You need to use what they call an Attached Property.

Simply Put.

1. Create an attached property class. http://dotnetbyexample.blogspot.com.au/2010/05/attached-dependency-properties-for.html should get you started
2. Create a template to your Menu Items Example Below
3. Create Standard Menu Items.

4. Handle Everything in your Attached Property PropertyMetadata Event Handler.

    <Style TargetType="MenuItem">
         <Setter Property="Properties:ControlMenuItem.InvokeClick" Value="{Binding  RelativeSource={RelativeSource Self}}"/>
    </Style>
   

Answer 2

ContextMenu ist not part the the Visual Tree and so FindAncestory data binding won't work.

You could set the DataContexton the ContextMenuexplicitly though.

e.g. you could create an instance of your ViewModel / DataContext directly in XAML if that's an option.

<Style TargetType="{x:Type TreeViewItem}">
  <Setter Property="ContextMenu">
    <Setter.Value>
      <ContextMenu>
        <ContextMenu.DataContext>
          <local:MyViewModel/>
        </ContextMenu.DataContext>

        <MenuItem Command="{Binding Path=CommandPopupClick}"
                  CommandParameter="{Binding Path=SelectedItem}"
                  Header="Delete" />
        <Separator />
        <MenuItem Command="{Binding Path=CommandPopupClick}"
                  CommandParameter="{Binding Path=SelectedItem}"
                  Header="Properties" />
      </ContextMenu>
    </Setter.Value>
  </Setter>
</Style>

Or get it from a StaticResource.

  <Window.Resources>
    <local:MyViewModel x:Key="ctx"/>

    <Style TargetType="{x:Type TreeViewItem}">
      <Setter Property="ContextMenu">
        <Setter.Value>
          <ContextMenu DataContext="{StaticResource ctx}">

            <MenuItem Command="{Binding Path=CommandPopupClick}"
                      CommandParameter="{Binding Path=SelectedItem}"
                      Header="Delete" />
            ....

          </ContextMenu>
        </Setter.Value>
      </Setter>
    </Style>
  </Window.Resources>

Answer 3

You can't use a RelativeSource Binding to access the TreeView.DataContext from the ContextMenu because it is not in the main UI visual tree. This is a very well documented problem and the solution is to pass the DataContext object through to the ContextMenu using the ContextMeny.PlacementTarget property and the Tag property on the object that has the Contextmenu applied to it.

Having already written and re-written about this many times, nowadays, I much prefer to request that you read my answers to the ContextMenu.PlacementTarget is not getting set, no idea why and Add context menu in datagrid, how to get the select Item value questions here on Stack Overflow for full explanations and code examples. If you need further help, just search the internet for 'WPF ContextMenu DataContext' or something similar and you should find dozens of tutorials on this exact topic.