diff -r 3145aadca3d2 -r 0c551e8818e0 External/Aga.Controls/Tree/TreeModel.cs
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/External/Aga.Controls/Tree/TreeModel.cs	Sun May 27 15:16:19 2012 +0000
@@ -0,0 +1,127 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+using System.Collections.ObjectModel;
+
+namespace Aga.Controls.Tree
+{
+	/// <summary>
+	/// Provides a simple ready to use implementation of <see cref="ITreeModel"/>. Warning: this class is not optimized 
+	/// to work with big amount of data. In this case create you own implementation of <c>ITreeModel</c>, and pay attention
+	/// on GetChildren and IsLeaf methods.
+	/// </summary>
+	public class TreeModel : ITreeModel
+	{
+		private Node _root;
+		public Node Root
+		{
+			get { return _root; }
+		}
+
+		public Collection<Node> Nodes
+		{
+			get { return _root.Nodes; }
+		}
+
+		public TreeModel()
+		{
+			_root = new Node();
+			_root.Model = this;
+		}
+
+		public TreePath GetPath(Node node)
+		{
+			if (node == _root)
+				return TreePath.Empty;
+			else
+			{
+				Stack<object> stack = new Stack<object>();
+				while (node != _root)
+				{
+					stack.Push(node);
+					node = node.Parent;
+				}
+				return new TreePath(stack.ToArray());
+			}
+		}
+
+		public Node FindNode(TreePath path)
+		{
+			if (path.IsEmpty())
+				return _root;
+			else
+				return FindNode(_root, path, 0);
+		}
+
+		private Node FindNode(Node root, TreePath path, int level)
+		{
+			foreach (Node node in root.Nodes)
+				if (node == path.FullPath[level])
+				{
+					if (level == path.FullPath.Length - 1)
+						return node;
+					else
+						return FindNode(node, path, level + 1);
+				}
+			return null;
+		}
+
+		#region ITreeModel Members
+
+		public System.Collections.IEnumerable GetChildren(TreePath treePath)
+		{
+			Node node = FindNode(treePath);
+			if (node != null)
+				foreach (Node n in node.Nodes)
+					yield return n;
+			else
+				yield break;
+		}
+
+		public bool IsLeaf(TreePath treePath)
+		{
+			Node node = FindNode(treePath);
+			if (node != null)
+				return node.IsLeaf;
+			else
+				throw new ArgumentException("treePath");
+		}
+
+		public event EventHandler<TreeModelEventArgs> NodesChanged;
+		internal void OnNodesChanged(TreeModelEventArgs args)
+		{
+			if (NodesChanged != null)
+				NodesChanged(this, args);
+		}
+
+		public event EventHandler<TreePathEventArgs> StructureChanged;
+		public void OnStructureChanged(TreePathEventArgs args)
+		{
+			if (StructureChanged != null)
+				StructureChanged(this, args);
+		}
+
+		public event EventHandler<TreeModelEventArgs> NodesInserted;
+		internal void OnNodeInserted(Node parent, int index, Node node)
+		{
+			if (NodesInserted != null)
+			{
+				TreeModelEventArgs args = new TreeModelEventArgs(GetPath(parent), new int[] { index }, new object[] { node });
+				NodesInserted(this, args);
+			}
+
+		}
+
+		public event EventHandler<TreeModelEventArgs> NodesRemoved;
+		internal void OnNodeRemoved(Node parent, int index, Node node)
+		{
+			if (NodesRemoved != null)
+			{
+				TreeModelEventArgs args = new TreeModelEventArgs(GetPath(parent), new int[] { index }, new object[] { node });
+				NodesRemoved(this, args);
+			}
+		}
+
+		#endregion
+	}
+}