Binding SelectedItem in a HierarchicalDataTemplate-applied WPF TreeView

Question

I have a data-bound TreeView and I want to bind SelectedItem. This attached behavior works perfectly without HierarchicalDataTemplate

Answer 1

If you find, like I did, that this answer sometimes crashes because itemPresenter is null, then this modification to that solution might work for you.

Change OnSelectedItemChanged to this (if the Tree isn't loaded yet, then it waits until the Tree is loaded and tries again):

private static void OnSelectedItemChanged(DependencyObject sender, DependencyPropertyChangedEventArgs e)
{
    Action selectTreeViewItem = tvi2 =>
    {
        if (tvi2 != null)
        {
            tvi2.IsSelected = true;
            tvi2.Focus();
        }
    };

    var tvi = e.NewValue as TreeViewItem;

    if (tvi == null)
    {
        var tree = ((BindableTreeViewSelectedItemBehavior) sender).AssociatedObject;
        if (!tree.IsLoaded)
        {
            RoutedEventHandler handler = null;
            handler = (sender2, e2) =>
            {
                tvi = GetTreeViewItem(tree, e.NewValue);
                selectTreeViewItem(tvi);
                tree.Loaded -= handler;
            };
            tree.Loaded += handler;

            return;
        }
        tvi = GetTreeViewItem(tree, e.NewValue);
    }

    selectTreeViewItem(tvi);
}