Trouble binding WPF Menu to ItemsSource

Question

I would like to avoid having to build a menu manually in XAML or code, by binding to a list of ICommand-derived objects. However, I'm experiencing a bit of a problem where the resulting menu has two levels of menu-items (i.e. each MenuItem is contained in a MenuItem):

My guess is that this is happening because WPF is automatically generating a MenuItem for my binding, but the "viewer" I'm using actually already is a MenuItem (it's derived from MenuItem):

<ContextMenu
    x:Name="selectionContextMenu"
    ItemsSource="{Binding Source={x:Static OrangeNote:Note.MultiCommands}}"
    ItemContainerStyleSelector="{StaticResource separatorStyleSelector}">
    <ContextMenu.ItemTemplate>
        <DataTemplate>
            <Viewers:NoteCommandMenuItemViewer
                CommandParameter="{Binding Source={x:Static OrangeNote:App.Screen}, Path=SelectedNotes}" />
        </DataTemplate>
    </ContextMenu.ItemTemplate>
</ContextMenu>

(The ItemContainerStyleSelector is from http://bea.stollnitz.com/blog/?p=23, which allows me to have Separator elements inside my bound source.)

So, the menu is bound to a collection of ICommands, and each item's CommandParameter is set to the same global target (which happens to be a collection, but that's not important).

My question is, is there any way I can bind this such that WPF doesn't automatically wrap each item in a MenuItem?

Answer 1

Unfortunately, the best way I've found to work around this issue is to use a style for the MenuItems, rather than an ItemTemplate. Then each property in the style can be bound to properties on your object. Something like this, for example:

<Style x:Key="SelectionContextMenuStyle" TargetType="MenuItem">
    <Setter Property="Header" Value="{Binding Path=Text}" />
    <Setter Property="Command" Value="{Binding Path=Command}" />
    <Setter Property="CommandParameter" Value="{Binding Path=Parameter}" />
</Style>

It really seems like an ItemTemplate should work, and it would be the better way to go, but this is the only way I've found that actually works properly.

Answer 2

I would be inclined to subclass ContextMenu and override GetContainerForItemOverride:

public class ContextMenuWithNoteCommands : ContextMenu
{
  protected virtual DependencyObject GetContainerForItemOverride()
  {
    return new NoteCommandMenuItemViewer();
  }
}

Then set the CommandParameter binding in the NoteCommandMenuItemViewer style, or in ContextMenu.ItemContainerStyle, whichever is more appropriate.

This presumes you can't simply use ItemContainerStyle on a regular MenuItem to get the effect you want:

<ContextMenu ...>
  <ContextMenu.ItemContainerStyle>
    <Style>
      ...
    </Style>
  </ContextMenu.ItemContainerStyle>
</ContextMenu>