Question

I have a class derived from ItemsControl in which I implement my own selection-algorithm which uses the MouseLeftButtonDown to change the selection.

Now I needed a specific control to handle Mouseclicks in the ViewModel, so I wrote the following:

<controls:DraggableItemsContainer bla="blub">
    <controls:DraggableItemsContainer.InputBindings>
        <MouseBinding Gesture="LeftClick" Command="{Binding DeselectSubGroupsCommand}" />
    </controls:DraggableItemsContainer.InputBindings>
</controls:DraggableItemsContainer>

What happens now is, that I don’t get the MouseLeftButtonDown-event anymore – which is comprehensable because the command “e.handles” the click.

But in this case, that’s not what I want. Is there a way to fire the event anyway?

PS: Yes I need to do the selection in the MouseLeftButtonDown-event and not in any Preview-event

Answer 1

Two options:

• You can have your custom ItemsControl hook PreviewMouseDown instead of MouseDown.
• You can continue to hook MouseDown, but do it by calling AddHandler, and pass true for the handledEventsToo parameter.

If it’s important that you get notified after the MouseBinding has done its work, then you need to use AddHandler. If you’re okay with getting the message first, PreviewMouseDown is simpler.