Generic Tree <T> in C#

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Xml.Serialization;

using PH.DataTree;
using System.IO;
using System.Runtime.Serialization.Formatters.Binary;
using System.Runtime.Serialization;

namespace XTree
{

   public partial class Form1 : Form
   {
      TreeViewController<string>  m_tvc;
      DTreeNode<string>           m_data;

      LabelGenerator m_lGen = new LabelGenerator();

      public Form1()
      {
         // System.Threading.Thread.Sleep(1000);
         // PerfTest.TestPerf();

         InitializeComponent();

         m_data = new DTreeNode<string>(""); // note: root node is not mapped
         m_tvc = new TreeViewController<string>(treeView1, m_data);

         UpdateUI();
         NextSuggestion();
      }

      private void treeView1_AfterSelect(object sender, TreeViewEventArgs e)
      {
         UpdateUI();
      }

      void NextSuggestion()
      {
         textBox1.Text = m_lGen.Get();
         textBox1.SelectAll();
         textBox1.Focus();
      }

      private void UpdateUI()
      {
         DTreeNode<string> curNode = m_tvc.SelectedNode;

         bool haveNode = curNode != null;

         button2.Enabled = haveNode;
         button3.Enabled = haveNode;
         button5.Enabled = haveNode;

         if (haveNode)
         {
            string s = curNode.GetNodePathAsString(true, '\\');
            label2.Text = s;
         }


         label1.Text = m_lGen.Index.ToString();
      }

      private void button1_Click(object sender, EventArgs e)
      {
         // Add new node
         DTreeNode<string> curNode = m_tvc.SelectedNode;

         DTreeNode<string> newNode;

         if (curNode == null)
            newNode = m_data.Nodes.Add(textBox1.Text);
         else
            newNode = curNode.Siblings.InsertAfter(curNode, textBox1.Text);

         m_tvc.SelectedNode = newNode;
         NextSuggestion();
      }

      private void button2_Click(object sender, EventArgs e)
      {
         // Add new child node
         DTreeNode<string> curNode = m_tvc.SelectedNode;
         m_tvc.SelectedNode =
            curNode.Nodes.Add(textBox1.Text);
         NextSuggestion();
      }

      private void button5_Click(object sender, EventArgs e)
      {
         // change current value
         DTreeNode<string> currentNode = m_tvc.SelectedNode;
         if (currentNode != null)
            currentNode.Value = textBox1.Text;

         // Note: if the node type is a reference type, 
         // and is changed indirectly (not through an assignment), you have to call:
         //   m_tvc.Update(currentNode)
         // This is because changing attributes of a reference cannot fire an OnValueChanged event

         // Note II: UpdateUI() only updates the buttons of this form. 
         // It is not required to update the tree 
      }

      private void button3_Click(object sender, EventArgs e)
      {
         // remove current node
         DTreeNode<string> currentNode = m_tvc.SelectedNode;
         if (currentNode != null)
            currentNode.Remove();
      }



      private class ComparebyName : IComparer<string>
      {
         public int Compare(string x, string y)
         {
            return x.CompareTo(y);
         }
      }

      private class ComparebyNameDesc : IComparer<string>
      {
         public int Compare(string x, string y)
         {
            return y.CompareTo(x);
         }
      }

      private class CompareByLength : IComparer<string>
      {
         public int Compare(string x, string y)
         {
            return x.Length.CompareTo(y.Length);
         }
      }



      private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
      {
         int curSel = comboBox1.SelectedIndex;

         switch (curSel)
         {
            case 0 : // none
               m_tvc.AutoSortCompare = null;
               break;

            case 1:  // Name Ascending
               m_tvc.AutoSortCompare = new ComparebyName();
               break;

            case 2:
               m_tvc.AutoSortCompare = new ComparebyNameDesc();
               break;

            case 3:
               m_tvc.AutoSortCompare = new CompareByLength();
               break;
         }
      }

      private void openToolStripMenuItem_Click(object sender, EventArgs e)
      {
         DialogResult result = openFileDialog1.ShowDialog(this);
         if (result != DialogResult.OK)
            return;

         string ext = Path.GetExtension(openFileDialog1.FileName).ToLower();

         bool asXml = ext=="xml" || (ext != "bin" && openFileDialog1.FilterIndex == 1);

         if (asXml)
         {
            XmlSerializer ser = new XmlSerializer(typeof(DTreeNode<string>));
            FileStream stream = new FileStream(openFileDialog1.FileName, FileMode.Open);
            m_data = (DTreeNode<string>)(ser.Deserialize(stream));
            stream.Close();
         }
         else
         {
            IFormatter formatter = new BinaryFormatter();
            Stream stream = new FileStream(openFileDialog1.FileName, FileMode.Open, FileAccess.Read, FileShare.Read);
            m_data = (DTreeNode<string>)formatter.Deserialize(stream);
            stream.Close();
         }

         // update tvc
         m_tvc = new TreeViewController<string>(treeView1, m_data);
      }

      private void saveToolStripMenuItem_Click(object sender, EventArgs e)
      {
         DialogResult result = saveFileDialog1.ShowDialog(this);
         if (result != DialogResult.OK)
            return;

         bool asXML = saveFileDialog1.FilterIndex == 1;

         if (asXML)
         {
            XmlSerializer ser = new XmlSerializer(typeof(DTreeNode<string>));
            StreamWriter writer = new StreamWriter(saveFileDialog1.FileName);
            ser.Serialize(writer, m_data);
            writer.Close();
         }
         else
         {
            m_tvc = null;
            IFormatter formatter = new BinaryFormatter();
            Stream stream = new FileStream(saveFileDialog1.FileName, FileMode.Create, FileAccess.Write, FileShare.None);
            formatter.Serialize(stream, m_data);
            stream.Close();
            m_tvc = new TreeViewController<string>(treeView1, m_data);
         }
      }


   }

   class LabelGenerator // Helper class to generate some nice words
   {
      string[] words;
      int index = -1;

      #region CTOR
      public LabelGenerator()
      {
         string text = 
            @"Ich bin so wild nach deinem Erdbeermund,
               ich schrie mir schon die Lungen wund
               nach deinem weissen Leib, du Weib.
               Im Klee, da hat der Mai ein Bett gemacht,
               da bl�ht ein sch�ner Zeitvertreib
               mit deinem Leib die lange Nacht.
               Da will ich sein im tiefen Tal
               dein Nachtgebet und auch dein Sterngemahl.

               Die graue Welt macht keine Freude mehr,
               ich gab den sch�nsten Sommer her,
               und dir hats auch kein Gl�ck gebracht;
               hast nur den roten Mund noch aufgespart
               f�r mich so tief im Haar verwahrt ...
               Ich such ihn schon die lange Nacht
               im Wintertal im Aschengrund ...
               Ich bin so wild nach deinem Erdbeermund.

               Im Wintertal, im schwarzen Erdbeerkraut,
               da hat der Schnee ein Nest gebaut
               und fragt nicht, wo die Liebe sei.
               Und habe doch das rote Tier so tief
               erfahren, als ich bei dir schlief.
               W�r nur der Winter erst vorbei
               und wieder gr�n der Wiesengrund!
               ... ich bin so wild nach deinem Erdbeermund!";

         words = text.Split(new Char[] { ' ', '\r', '\n' }, StringSplitOptions.RemoveEmptyEntries);
      }
      #endregion

      public string Get()
      {
         ++index;
         if (index >= words.Length)
            index = 0;
         return words[index];
      }

      public int Index { get { return index; } }
   }




}