My Personal Commander Variant

// This file is part of the Lobster.MVVM library
// Copyright: Andreas Raczek
// This file is published under the The Code Project Open License (CPOL) 
// See the file "CPOL.html" for the full license governing this code.

using System.Windows;
using System.Windows.Controls;

namespace Lobster.MVVM
{
    /// <summary> 
    /// This is not working as the bound element must be changed to raise the 
    /// SelectedItemChanged callback. If its bound to a null object waiting to
    /// be changed by the behavior itself, nothing will happen.
    /// </summary>
    public class TreeViewBehavior
    {
#region SelectedItem Property
        public static object GetSelectedItem(DependencyObject obj)
        {
            return (object) obj.GetValue(SelectedItemProperty);
        }

        public static void SetSelectedItem(DependencyObject obj, object value)
        {
            obj.SetValue(SelectedItemProperty, value);
        }

        public static readonly DependencyProperty SelectedItemProperty 
            = DependencyProperty.RegisterAttached(
                "SelectedItem", 
                typeof(object), 
                typeof(TreeViewBehavior), 
                new FrameworkPropertyMetadata(new PropertyChangedCallback(SelectedItemChanged)
                    , FrameworkPropertyMetadataOptions.BindsTwoWayByDefault
                    ));
                  
        private static void SelectedItemChanged(DependencyObject sender, DependencyPropertyChangedEventArgs e)
        {
            var treeview = sender as TreeView;

            if (treeview != null)
            {
                if (e.NewValue != null) 
                {
                    // Attach Item Change Handler
                    treeview.SelectedItemChanged += OnTreeViewSelectedItemChanged;
                } else {
                    // Detach Item Change Handler
                    treeview.SelectedItemChanged -= OnTreeViewSelectedItemChanged;
                }
            }
        }

        private static void OnTreeViewSelectedItemChanged(object sender, RoutedPropertyChangedEventArgs<object> e)
        {
            /*
            SetSelectedItem2(sender as TreeView, e.NewValue);
            
            var dob = sender as DependencyObject;
            dob.SetCurrentValue(SelectedItemProperty, e.NewValue);
             */
        }
#endregion
    }
}