Using Window Messages to Implement Global System Hooks in C#

using System;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;
using System.Text;
using System.Runtime.InteropServices;

namespace GlobalHooksTest
{
	public class Form1 : System.Windows.Forms.Form
	{
		private System.Windows.Forms.GroupBox groupBox1;
		private System.Windows.Forms.Button BtnInitCbt;
		private System.Windows.Forms.Button BtnUninitCbt;
		private System.Windows.Forms.GroupBox groupBox2;
		private System.Windows.Forms.Button BtnUninitShell;
		private System.Windows.Forms.Button BtnInitShell;
		private System.Windows.Forms.ListBox ListCbt;
		private System.Windows.Forms.ListBox ListShell;
		private System.Windows.Forms.Label LblMouse;
		private System.ComponentModel.Container components = null;

		// API calls to give us a bit more information about the data we get from the hook
		[DllImport("user32.dll")]
		private static extern int GetWindowText(IntPtr hWnd, StringBuilder title, int size);
		[DllImport("user32.dll")]
		private static extern uint RealGetWindowClass(IntPtr hWnd, StringBuilder pszType, uint cchType);

		private GlobalHooks _GlobalHooks;

		public Form1()
		{
			InitializeComponent();

			// Instantiate our GlobalHooks object
			_GlobalHooks = new GlobalHooks(this.Handle);

			// Set the hook events
			_GlobalHooks.CBT.Activate += new GlobalHooksTest.GlobalHooks.WindowEventHandler(_GlobalHooks_CbtActivate);
			_GlobalHooks.CBT.CreateWindow += new GlobalHooksTest.GlobalHooks.WindowEventHandler(_GlobalHooks_CbtCreateWindow);
			_GlobalHooks.CBT.DestroyWindow += new GlobalHooksTest.GlobalHooks.WindowEventHandler(_GlobalHooks_CbtDestroyWindow);
			_GlobalHooks.Shell.WindowActivated += new GlobalHooksTest.GlobalHooks.WindowEventHandler(_GlobalHooks_ShellWindowActivated);
			_GlobalHooks.Shell.WindowCreated += new GlobalHooksTest.GlobalHooks.WindowEventHandler(_GlobalHooks_ShellWindowCreated);
			_GlobalHooks.Shell.WindowDestroyed += new GlobalHooksTest.GlobalHooks.WindowEventHandler(_GlobalHooks_ShellWindowDestroyed);
			_GlobalHooks.Shell.Redraw += new GlobalHooksTest.GlobalHooks.WindowEventHandler(_GlobalHooks_ShellRedraw);
			_GlobalHooks.MouseLL.MouseMove += new MouseEventHandler(MouseLL_MouseMove);

			_GlobalHooks.MouseLL.Start();
		}

		protected override void Dispose( bool disposing )
		{
			if( disposing )
			{
				// Make sure we stop hooking before quitting! Otherwise, the hook procedures in GlobalCbtHook.dll
				// will keep being called, even after our application quits, which will needlessly degrade system
				// performance. And it's just plain sloppy.
				_GlobalHooks.CBT.Stop();
				_GlobalHooks.Shell.Stop();
				_GlobalHooks.MouseLL.Stop();

				if (components != null) 
				{
					components.Dispose();
				}
			}
			base.Dispose( disposing );
		}

		#region Windows Form Designer generated code
		/// <summary>
		/// Required method for Designer support - do not modify
		/// the contents of this method with the code editor.
		/// </summary>
		private void InitializeComponent()
		{
			this.groupBox1 = new System.Windows.Forms.GroupBox();
			this.ListCbt = new System.Windows.Forms.ListBox();
			this.BtnUninitCbt = new System.Windows.Forms.Button();
			this.BtnInitCbt = new System.Windows.Forms.Button();
			this.groupBox2 = new System.Windows.Forms.GroupBox();
			this.ListShell = new System.Windows.Forms.ListBox();
			this.BtnUninitShell = new System.Windows.Forms.Button();
			this.BtnInitShell = new System.Windows.Forms.Button();
			this.LblMouse = new System.Windows.Forms.Label();
			this.groupBox1.SuspendLayout();
			this.groupBox2.SuspendLayout();
			this.SuspendLayout();
			// 
			// groupBox1
			// 
			this.groupBox1.Controls.Add(this.ListCbt);
			this.groupBox1.Controls.Add(this.BtnUninitCbt);
			this.groupBox1.Controls.Add(this.BtnInitCbt);
			this.groupBox1.Location = new System.Drawing.Point(8, 8);
			this.groupBox1.Name = "groupBox1";
			this.groupBox1.Size = new System.Drawing.Size(280, 280);
			this.groupBox1.TabIndex = 2;
			this.groupBox1.TabStop = false;
			this.groupBox1.Text = "CBT Hooks";
			// 
			// ListCbt
			// 
			this.ListCbt.Location = new System.Drawing.Point(8, 56);
			this.ListCbt.Name = "ListCbt";
			this.ListCbt.Size = new System.Drawing.Size(264, 212);
			this.ListCbt.TabIndex = 3;
			// 
			// BtnUninitCbt
			// 
			this.BtnUninitCbt.Location = new System.Drawing.Point(144, 16);
			this.BtnUninitCbt.Name = "BtnUninitCbt";
			this.BtnUninitCbt.Size = new System.Drawing.Size(128, 32);
			this.BtnUninitCbt.TabIndex = 2;
			this.BtnUninitCbt.Text = "Uninitialize CBT Hooks";
			this.BtnUninitCbt.Click += new System.EventHandler(this.BtnUninitCbt_Click);
			// 
			// BtnInitCbt
			// 
			this.BtnInitCbt.Location = new System.Drawing.Point(8, 16);
			this.BtnInitCbt.Name = "BtnInitCbt";
			this.BtnInitCbt.Size = new System.Drawing.Size(128, 32);
			this.BtnInitCbt.TabIndex = 1;
			this.BtnInitCbt.Text = "Initialize CBT Hooks";
			this.BtnInitCbt.Click += new System.EventHandler(this.BtnInitCbt_Click);
			// 
			// groupBox2
			// 
			this.groupBox2.Controls.Add(this.ListShell);
			this.groupBox2.Controls.Add(this.BtnUninitShell);
			this.groupBox2.Controls.Add(this.BtnInitShell);
			this.groupBox2.Location = new System.Drawing.Point(288, 8);
			this.groupBox2.Name = "groupBox2";
			this.groupBox2.Size = new System.Drawing.Size(296, 280);
			this.groupBox2.TabIndex = 3;
			this.groupBox2.TabStop = false;
			this.groupBox2.Text = "Shell Hooks";
			// 
			// ListShell
			// 
			this.ListShell.Location = new System.Drawing.Point(8, 56);
			this.ListShell.Name = "ListShell";
			this.ListShell.Size = new System.Drawing.Size(280, 212);
			this.ListShell.TabIndex = 3;
			// 
			// BtnUninitShell
			// 
			this.BtnUninitShell.Location = new System.Drawing.Point(152, 16);
			this.BtnUninitShell.Name = "BtnUninitShell";
			this.BtnUninitShell.Size = new System.Drawing.Size(136, 32);
			this.BtnUninitShell.TabIndex = 2;
			this.BtnUninitShell.Text = "Uninitialize Shell Hooks";
			this.BtnUninitShell.Click += new System.EventHandler(this.BtnUninitShell_Click);
			// 
			// BtnInitShell
			// 
			this.BtnInitShell.Location = new System.Drawing.Point(8, 16);
			this.BtnInitShell.Name = "BtnInitShell";
			this.BtnInitShell.Size = new System.Drawing.Size(136, 32);
			this.BtnInitShell.TabIndex = 1;
			this.BtnInitShell.Text = "Initialize Shell Hooks";
			this.BtnInitShell.Click += new System.EventHandler(this.BtnInitShell_Click);
			// 
			// LblMouse
			// 
			this.LblMouse.Location = new System.Drawing.Point(16, 296);
			this.LblMouse.Name = "LblMouse";
			this.LblMouse.Size = new System.Drawing.Size(272, 23);
			this.LblMouse.TabIndex = 4;
			// 
			// Form1
			// 
			this.AutoScaleBaseSize = new System.Drawing.Size(5, 13);
			this.ClientSize = new System.Drawing.Size(592, 318);
			this.Controls.Add(this.LblMouse);
			this.Controls.Add(this.groupBox2);
			this.Controls.Add(this.groupBox1);
			this.Name = "Form1";
			this.Text = "Global Hooks Test";
			this.groupBox1.ResumeLayout(false);
			this.groupBox2.ResumeLayout(false);
			this.ResumeLayout(false);

		}
		#endregion

		[STAThread]
		static void Main() 
		{
			Application.Run(new Form1());
		}

		private void BtnInitCbt_Click(object sender, System.EventArgs e)
		{
			_GlobalHooks.CBT.Start();
		}

		private void BtnUninitCbt_Click(object sender, System.EventArgs e)
		{
			_GlobalHooks.CBT.Stop();
		}

		private void BtnInitShell_Click(object sender, System.EventArgs e)
		{
			_GlobalHooks.Shell.Start();
		}

		private void BtnUninitShell_Click(object sender, System.EventArgs e)
		{
			_GlobalHooks.Shell.Stop();
		}

		protected override void WndProc(ref Message m)
		{
			// Check to see if we've received any Windows messages telling us about our hooks
			if (_GlobalHooks != null)
				_GlobalHooks.ProcessWindowMessage(ref m);

			base.WndProc (ref m);
		}

		#region Windows API Helper Functions

		private string GetWindowName(IntPtr Hwnd)
		{
			// This function gets the name of a window from its handle
			StringBuilder Title = new StringBuilder(256);
			GetWindowText(Hwnd, Title, 256);

			return Title.ToString().Trim();
		}

		private string GetWindowClass(IntPtr Hwnd)
		{
			// This function gets the name of a window class from a window handle
			StringBuilder Title = new StringBuilder(256);
			RealGetWindowClass(Hwnd, Title, 256);

			return Title.ToString().Trim();
		}

		#endregion

		private void _GlobalHooks_CbtActivate(IntPtr Handle)
		{
			this.ListCbt.Items.Add("Activate: " + GetWindowName(Handle));
		}

		private void _GlobalHooks_CbtCreateWindow(IntPtr Handle)
		{
			this.ListCbt.Items.Add("Create: " + GetWindowClass(Handle));
		}

		private void _GlobalHooks_CbtDestroyWindow(IntPtr Handle)
		{
			this.ListCbt.Items.Add("Destroy: " + GetWindowName(Handle));
		}

		private void _GlobalHooks_ShellWindowActivated(IntPtr Handle)
		{
			this.ListShell.Items.Add("Activated: " + GetWindowName(Handle));
		}

		private void _GlobalHooks_ShellWindowCreated(IntPtr Handle)
		{
			this.ListShell.Items.Add("Created: " + GetWindowName(Handle));
		}

		private void _GlobalHooks_ShellWindowDestroyed(IntPtr Handle)
		{
			this.ListShell.Items.Add("Destroyed: " + GetWindowName(Handle));
		}

		private void _GlobalHooks_ShellRedraw(IntPtr Handle)
		{
			this.ListShell.Items.Add("Redraw: " + GetWindowName(Handle));
		}

		private void MouseLL_MouseMove(object sender, MouseEventArgs e)
		{
			this.LblMouse.Text = "Mouse at: " + e.X + ", " + e.Y;
		}
	}
}