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

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

using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;
using Microsoft.Win32;

  public class RegistryBrowser : System.Windows.Forms.Form
  {
    private System.Windows.Forms.TreeView tvRegistry;
    private System.Windows.Forms.ImageList ilTreeImages;

    public RegistryBrowser()
    {
      InitializeComponent();
      RootNodes();
    }
    private void InitializeComponent()
    {
      this.tvRegistry = new System.Windows.Forms.TreeView();
      this.ilTreeImages = new System.Windows.Forms.ImageList();
      this.SuspendLayout();
      // 
      // tvRegistry
      // 
      this.tvRegistry.Dock = System.Windows.Forms.DockStyle.Fill;
      this.tvRegistry.Name = "tvRegistry";
      this.tvRegistry.Size = new System.Drawing.Size(392, 333);
      this.tvRegistry.TabIndex = 0;
      this.tvRegistry.BeforeExpand += new System.Windows.Forms.TreeViewCancelEventHandler(this.tvRegistry_BeforeExpand);
      // 
      // ilTreeImages
      // 
      this.ilTreeImages.ColorDepth = System.Windows.Forms.ColorDepth.Depth8Bit;
      this.ilTreeImages.TransparentColor = System.Drawing.Color.Transparent;
      // 
      // RegistryBrowser
      // 
      this.AutoScaleBaseSize = new System.Drawing.Size(5, 13);
      this.ClientSize = new System.Drawing.Size(392, 333);
      this.Controls.AddRange(new System.Windows.Forms.Control[] {
                                      this.tvRegistry});
      this.Name = "RegistryBrowser";
      this.Text = "Registry Browser";
      this.ResumeLayout(false);

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

    private void tvRegistry_BeforeExpand(object sender, System.Windows.Forms.TreeViewCancelEventArgs e)
    {
      tvRegistry.BeginUpdate();
      foreach (TreeNode tn in e.Node.Nodes)
      {
        AddBranch(tn);
      }
      tvRegistry.EndUpdate();
    }

    public void AddBranch(TreeNode tn)
    {
      tn.Nodes.Clear();
      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.tvRegistry.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 void RootNodes()
    {
      tvRegistry.BeginUpdate();

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

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

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

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

      tvRegistry.SelectedNode = tnHKLM;
      tvRegistry.EndUpdate();
    }
  }