Question

I am trying to bind to command that is on my viewmodel. I am using an event trigger that is way down on the visual tree. I have tried many variations of RelativeSource, FindAncestor and AncestorType trying to bind to it. Every time I get a bind path expression error.

This is my xaml document outline:

<Window>
   <Grid>
      <GridView>
         <HierarchyChildTemplate>
             <DataTemplate>
                  <TabControl>
                      <TabItem>
                          <GridView>
                              <RowDetailsTemplate>
                                 <TabControl>
                                     <!--trying to bind a event trigger here to a command on the viewModel -->

Here is an example of the binding I’ve tried:

<i:Interaction.Triggers>
      <i:EventTrigger EventName="SelectionChanged">
          <i:InvokeCommandAction Command="{Binding Path=SelectionChangedCommand, RelativeSource={RelativeSource Mode=FindAncestor, AncestorType={x:Type Grid}}}"/>
      </i:EventTrigger>
</i:Interaction.Triggers>

How would I bind to this command from the location noted in the xaml?

Answer 1

Ended up trying this and it worked:

<i:Interaction.Triggers>
  <i:EventTrigger EventName="SelectionChanged">
     <i:InvokeCommandAction Command="{Binding Path=DataContext.SelectionChangedCommand, 
         RelativeSource={RelativeSource Mode=FindAncestor, AncestorLevel=2,AncestorType={x:Type GridView}}}"/>
   </i:EventTrigger>
</i:Interaction.Triggers>     

Key points here are Prefacing the command with DataContext and AncestorLevel=2.