WPF TreeListView Control

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows.Controls;
using System.Windows.Input;
using System.ComponentModel;
using System.Windows;

namespace Aga.Controls.Tree
{
	public class TreeListItem : ListViewItem, INotifyPropertyChanged
	{
		#region Properties

		private TreeNode _node;
		public TreeNode Node
		{
			get { return _node; }
			internal set
			{
				_node = value;
				OnPropertyChanged("Node");
			}
		}

		#endregion

		public TreeListItem()
		{
		}

		protected override void OnKeyDown(KeyEventArgs e)
		{
			if (Node != null)
			{
				switch (e.Key)
				{
					case Key.Right:
						e.Handled = true;
						if (!Node.IsExpanded)
						{
							Node.IsExpanded = true;
							ChangeFocus(Node);
						}
						else if (Node.Children.Count > 0)
							ChangeFocus(Node.Children[0]);
						break;

					case Key.Left:

						e.Handled = true;
						if (Node.IsExpanded && Node.IsExpandable)
						{
							Node.IsExpanded = false;
							ChangeFocus(Node);
						}
						else
							ChangeFocus(Node.Parent);
						break;

					case Key.Subtract:
						e.Handled = true;
						Node.IsExpanded = false;
						ChangeFocus(Node);
						break;

					case Key.Add:
						e.Handled = true;
						Node.IsExpanded = true;
						ChangeFocus(Node);
						break;
				}
			}

			if (!e.Handled)
				base.OnKeyDown(e);
		}

		private void ChangeFocus(TreeNode node)
		{
			var tree = node.Tree;
			if (tree != null)
			{
				var item = tree.ItemContainerGenerator.ContainerFromItem(node) as TreeListItem;
				if (item != null)
					item.Focus();
				else
					tree.PendingFocusNode = node;
			}
		}

		#region INotifyPropertyChanged Members

		public event PropertyChangedEventHandler PropertyChanged;

		private void OnPropertyChanged(string name)
		{
			if (PropertyChanged != null)
				PropertyChanged(this, new PropertyChangedEventArgs(name));
		}

		#endregion
	}
}