I want to get a list with all active window handles

// EnumWin
//
// Enumerate all windows in the current desktop into a log file when
// a tray icon is clicked.
 
using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;
using System.Runtime.InteropServices;
using System.Text;
using System.IO;
using System.Diagnostics;
 
 
 
namespace EnumWin
{
public class fmEnumWin : System.Windows.Forms.Form
{
private System.ComponentModel.Container components = null;
 
 
 
NotifyIcon TrayIcon;
ContextMenu IconMenu;
 
 
private TextBox tbInfo;
private Label label1;
private Button cbCancel;
private Button cbTakeSnapshot;
bool HideIt=true;
 
 
public delegate bool EnumWinProc(int hwnd, int lParam);
 
[DllImport("user32.Dll")]
public static extern int EnumDesktopWindows(IntPtr DeskTopHandle,EnumWinProc x, int y);
 
[DllImport("User32.Dll")]
public static extern void GetWindowText(int h, StringBuilder s, int nMaxCount);
 
[DllImport("user32.dll")]
public static extern int GetWindowThreadProcessId(IntPtr hwnd,ref IntPtr pid);
 
[DllImport("user32.dll")] 
public static extern int GetWindowModuleFileName(int hWnd, StringBuilder title, int size);
 
[DllImport("user32")] 
public static extern int EnumChildWindows(int hwndParent,EnumWinProc x, int lParam);
 
 
 
public fmEnumWin()
{
InitializeComponent();
 
// Keep our window hidden until they ask for it                 
HideIt=true;
                        
// Make the tray icon
IconMenu=new ContextMenu(); 
IconMenu.MenuItems.Add(0,new MenuItem("Enumerate",new System.EventHandler(Enum_Click))); 
IconMenu.MenuItems.Add(1,new MenuItem("Ignore"   ,new System.EventHandler(Dont_Click))); 
IconMenu.MenuItems.Add(2,new MenuItem("Quit"     ,new System.EventHandler(Quit_Click)));
 
TrayIcon=new NotifyIcon();
 
TrayIcon.Text="EnumWin";
TrayIcon.Icon=new Icon(GetType(),"EnumWin.ico");
TrayIcon.ContextMenu=IconMenu;
 
TrayIcon.Visible=true;
}
 
 
 
// //////////////////////////////////////////////////////////           
// ////////////////////////////////////////////////////////// Dispose
// //////////////////////////////////////////////////////////////////           
protected override void Dispose( bool disposing )
{
if (disposing)
   {
   if (components!=null) 
      {    
      components.Dispose();
      }
   }
base.Dispose( disposing );
}
 
 
 
// //////////////////////////////////////////////               
// ////////////////////////////////////////////// InitializeComponent
// //////////////////////////////////////////////////////////////////           
private void InitializeComponent()
{
this.tbInfo = new System.Windows.Forms.TextBox();
this.label1 = new System.Windows.Forms.Label();
this.cbCancel = new System.Windows.Forms.Button();
this.cbTakeSnapshot = new System.Windows.Forms.Button();
this.SuspendLayout();
// 
// tbInfo
// 
this.tbInfo.Font = new System.Drawing.Font("Arial",12F,System.Drawing.FontStyle.Regular,System.Drawing.GraphicsUnit.Point,((byte)(0)));
this.tbInfo.Location = new System.Drawing.Point(21,44);
this.tbInfo.Multiline = true;
this.tbInfo.Name = "tbInfo";
this.tbInfo.ScrollBars = System.Windows.Forms.ScrollBars.Both;
this.tbInfo.Size = new System.Drawing.Size(362,111);
this.tbInfo.TabIndex = 0;
// 
// label1
// 
this.label1.AutoSize = true;
this.label1.Font = new System.Drawing.Font("Arial",12F,System.Drawing.FontStyle.Regular,System.Drawing.GraphicsUnit.Point,((byte)(0)));
this.label1.Location = new System.Drawing.Point(18,14);
this.label1.Name = "label1";
this.label1.Size = new System.Drawing.Size(365,18);
this.label1.TabIndex = 1;
this.label1.Text = "If you like, you can attach some text to this snapshot.";
// 
// cbCancel
// 
this.cbCancel.Font = new System.Drawing.Font("Arial",12F,System.Drawing.FontStyle.Regular,System.Drawing.GraphicsUnit.Point,((byte)(0)));
this.cbCancel.Location = new System.Drawing.Point(412,94);
this.cbCancel.Name = "cbCancel";
this.cbCancel.Size = new System.Drawing.Size(120,61);
this.cbCancel.TabIndex = 2;
this.cbCancel.Text = "Cancel the snapshot";
this.cbCancel.UseVisualStyleBackColor = true;
this.cbCancel.Click += new System.EventHandler(this.CancelSnapshot);
// 
// cbTakeSnapshot
// 
this.cbTakeSnapshot.Location = new System.Drawing.Point(412,14);
this.cbTakeSnapshot.Name = "cbTakeSnapshot";
this.cbTakeSnapshot.Size = new System.Drawing.Size(120,61);
this.cbTakeSnapshot.TabIndex = 3;
this.cbTakeSnapshot.Text = "Take the snapshot";
this.cbTakeSnapshot.UseVisualStyleBackColor = true;
this.cbTakeSnapshot.Click += new System.EventHandler(this.TakeSnapshot);
// 
// fmEnumWin
// 
this.ClientSize = new System.Drawing.Size(544,172);
this.Controls.Add(this.cbTakeSnapshot);
this.Controls.Add(this.cbCancel);
this.Controls.Add(this.label1);
this.Controls.Add(this.tbInfo);
this.Font = new System.Drawing.Font("Arial",12F,System.Drawing.FontStyle.Regular,System.Drawing.GraphicsUnit.Point,((byte)(0)));
this.Name = "fmEnumWin";
this.Text = "EnumWin";
this.ResumeLayout(false);
this.PerformLayout();
 
}
 
 
 
// /////////////////////////////////////////////////////////////                
// ///////////////////////////////////////////////////////////// Main
// //////////////////////////////////////////////////////////////////           
[STAThread]
static void Main() 
{
Application.Run(new fmEnumWin());
}
 
 
 
// ///////////////////////////////////////////////////////              
// /////////////////////////////////////////////////////// Enum_Click
// //////////////////////////////////////////////////////////////////           
protected void Enum_Click(Object sender, System.EventArgs e) 
{
HideIt=false;
this.Show();
this.tbInfo.Text="";
this.tbInfo.Refresh();
this.tbInfo.Focus();
return;
}
 
 
 
// ///////////////////////////////////////////////////////              
// /////////////////////////////////////////////////////// Dont_Click
// //////////////////////////////////////////////////////////////////           
protected void Dont_Click(Object sender, System.EventArgs e) 
{
HideIt=true;
this.Hide();
}
 
 
 
// ///////////////////////////////////////////////////////              
// /////////////////////////////////////////////////////// Quit_Click
// //////////////////////////////////////////////////////////////////           
protected void Quit_Click(Object sender, System.EventArgs e) 
{
TrayIcon.Dispose();
Application.Exit();
}
 
 
 
// /////////////////////////////////////////////////////                
// ///////////////////////////////////////////////////// TakeSnapshot
// //////////////////////////////////////////////////////////////////           
protected void TakeSnapshot(Object sender, System.EventArgs e) 
{
if (this.tbInfo.Text.Length>0) PutMsg(this.tbInfo.Text);
EnumDesktopWindows(IntPtr.Zero,new EnumWinProc(EnumWindowCallBack),0);
HideIt=true;
this.Hide();
}
 
 
 
// ///////////////////////////////////////////////////          
// /////////////////////////////////////////////////// CancelSnapshot
// //////////////////////////////////////////////////////////////////           
protected void CancelSnapshot(Object sender, System.EventArgs e) 
{
HideIt=true;
this.Hide();
}
 
 
 
// //////////////////////////////////////////////               
// ////////////////////////////////////////////// EnumWindowsCallBack
// //////////////////////////////////////////////////////////////////           
bool EnumWindowCallBack(int hwnd,int lParam)
{
StringBuilder WinTitle =new StringBuilder(256);
StringBuilder WinMod   =new StringBuilder(256);
 
GetWindowModuleFileName(hwnd,WinMod,256);
GetWindowText(hwnd,WinTitle,256);
 
PutMsg("Window: <"+WinTitle+">  Module: <"+WinMod+">");
 
EnumChildWindows(hwnd,new EnumWinProc(EnumChildCallBack),0);
 
 
return true;
}
 
 
 
// ////////////////////////////////////////////////             
// //////////////////////////////////////////////// EnumChildCallBack
// //////////////////////////////////////////////////////////////////           
bool EnumChildCallBack(int hwnd,int lParam)
{
StringBuilder WinTitle=new StringBuilder(256);
GetWindowText(hwnd,WinTitle,256);
 
PutMsg("        Child: <"+WinTitle+">");
return true;
}
 
 
// //////////////////////////////////////////////////////               
// ////////////////////////////////////////////////////// OnActivated
// //////////////////////////////////////////////////////////////////           
protected override void OnActivated(EventArgs e)
{
if (HideIt) this.Hide();
}
 
 
 
// ////////////////////////////////////////////////////////             
// //////////////////////////////////////////////////////// OnClosing
// //////////////////////////////////////////////////////////////////           
protected override void OnClosing(CancelEventArgs e)
{
TrayIcon.Dispose();
}
 
 
 
// /////////////////////////////////////////////////////////////////////
// ///////////////////////////////////////////////////////////////////// PutMsg
// ////////////////////////////////////////////////////////////////////////////
void PutMsg(string msg)
{
StreamWriter log;
DateTime now=new DateTime();
now=DateTime.Now;
log=new StreamWriter("c:\\EnumWin.log",true);
log.WriteLine(now.ToString("yyyy-MM-dd HH:mm:ss.fff ")+msg);
log.Close();
}
 
 
 
}
}