Registry Tree With Class : Registry Read « Windows « C# / CSharp Tutorial

1. C# / CSharp Tutorial
2. Windows
3. Registry Read

using System;
using System.Drawing;
using System.IO;
using System.Windows.Forms;
using Microsoft.Win32;

  public class RegistryTreeClass: TreeView
  {
    public RegistryTreeClass()
    {
      ImageList = new ImageList();
      ImageList.Images.Add(new Bitmap(GetType(), "CLOSED.BMP"));
      ImageList.Images.Add(new Bitmap(GetType(), "OPEN.BMP"));
      RootNodes();
    }

    protected override void OnBeforeExpand(TreeViewCancelEventArgs e)
    {
      base.OnBeforeExpand(e);
      BeginUpdate();

      foreach (TreeNode tn in e.Node.Nodes)
      {
        AddBranch(tn);
      }
      EndUpdate();
    }
    
    public void RootNodes()
    {
      BeginUpdate();

      TreeNode tnHKCR = new TreeNode("HKEY_CLASSES_ROOT",0,1);
      Nodes.Add(tnHKCR);
      AddBranch(tnHKCR);

      TreeNode tnHKCU = new TreeNode("HKEY_CURRENT_USER",0,1);
      Nodes.Add(tnHKCU);
      AddBranch(tnHKCU);

      TreeNode tnHKLM = new TreeNode("HKEY_LOCAL_MACHINE",0,1);
      Nodes.Add(tnHKLM);
      AddBranch(tnHKLM);

      TreeNode tnHKU = new TreeNode("HKEY_USERS",0,1);
      Nodes.Add(tnHKU);
      AddBranch(tnHKU);

      SelectedNode = tnHKLM;
      EndUpdate();
    }

    public void AddBranch(TreeNode tn)
    {
      if (tn.Nodes.Count > 0) return;
      string strRegistryPath = tn.FullPath;

      RegistryKey regBranch = null;
      if (strRegistryPath.StartsWith("HKEY_CLASSES_ROOT"))
        regBranch = Registry.ClassesRoot;
      else if (strRegistryPath.StartsWith("HKEY_CURRENT_USER"))
        regBranch = Registry.CurrentUser;
      else if (strRegistryPath.StartsWith("HKEY_LOCAL_MACHINE"))
        regBranch = Registry.LocalMachine;
      else if (strRegistryPath.StartsWith("HKEY_USERS"))
        regBranch = Registry.Users;

      RegistryKey regSubKey = null;
      try
      {
        if (null != tn.Parent)
        {
          // We need the path minus the top level tree.
          int nPosPathSeparator = strRegistryPath.IndexOf(this.PathSeparator);
          string strSubkey = strRegistryPath.Substring(nPosPathSeparator+1);
          regSubKey = regBranch.OpenSubKey(strSubkey);
        }
        else
          regSubKey = regBranch;
      }
      catch
      {
        return;
      }

      string[] astrSubkeyNames = regSubKey.GetSubKeyNames();
      for (int i=0; i < astrSubkeyNames.Length; i++)
      {
        TreeNode tnBranch = new TreeNode(astrSubkeyNames[i],0,1);
        tn.Nodes.Add(tnBranch);
      }
    }
  }
  public class MainForm : System.Windows.Forms.Form
  {
    private RegistryTreeClass rtvRegistry;
    public MainForm()
    {
      InitializeComponent();

      this.rtvRegistry = new RegistryTreeClass();
      this.SuspendLayout();
      this.rtvRegistry.Dock = System.Windows.Forms.DockStyle.Fill;
      this.rtvRegistry.ImageIndex = -1;
      this.rtvRegistry.Name = "rtvRegistry";
      this.rtvRegistry.SelectedImageIndex = -1;
      this.rtvRegistry.Size = new System.Drawing.Size(292, 273);
      this.rtvRegistry.TabIndex = 0;
      this.Controls.AddRange(new System.Windows.Forms.Control[] {
                                      this.rtvRegistry});
      this.ResumeLayout(false);
    }
    private void InitializeComponent()
    {
      this.AutoScaleBaseSize = new System.Drawing.Size(5, 13);
      this.ClientSize = new System.Drawing.Size(292, 273);
      this.Name = "MainForm";
      this.Text = "Registry with class";
      this.Load += new System.EventHandler(this.Form1_Load);

    }
    static void Main() 
    {
      Application.Run(new MainForm());
    }

    private void Form1_Load(object sender, System.EventArgs e)
    {
    
    }
  }