Silverlight Toolkit Treeview: Getting the parent of a selected item

Question

I'm using the TreeView component from the Silverlight toolkit and I'm trying to get the parent of a selected node. The TreeView is bound to a series of objects, so directly working with a TreeViewItem appears to be out of the question.

<toolkit:TreeView SelectedItemChanged="DoStuff" DisplayMemberPath="Name" ItemsSource="{Binding MyCollection}">
    <toolkit:TreeView.ItemTemplate>
        <common:HierarchicalDataTemplate ItemsSource="{Binding MySubCollection}">
            <StackPanel>
                <TextBlock Text="{Binding Name}" />
            </StackPanel>
        </common:HierarchicalDataTemplate>
    </toolkit:TreeView.ItemTemplate>
</toolkit:TreeView>

Is there a way to fetch the parent of an item selected in the DoStuff event?

Answer 1

As long as you've downloaded the latest Silverlight Toolkit then this is easy using the TreeViewExtensions that are included.

1. Download the Silverlight Toolkit and install.
2. Add a reference to System.Windows.Controls.Toolkit (from the Silverlight Toolkit)

3. Use the GetParentItem() extension method, like so:

   private void DoStuff(object sender, RoutedPropertyChangedEventArgs<object> e)
   {
       if (e.NewValue != null)
       {
           var parent = ((TreeView)sender).GetParentItem(e.NewValue);
           //
           // Do stuff with parent, this snippet updates 
           // a TextBlock showing the name of the current parent
           if (parent != null)
           {
                Status.Text = parent.ToString();
           }
       }
   }