//=============================================================================

 // COPYRIGHT: Prosoft-Lanz

 //=============================================================================

 //

 // $Workfile: CbtHook.cs $

 //

 // PROJECT : CodeProject Components

 // VERSION : 1.00

 // CREATION : 19.02.2003

 // AUTHOR : JCL

 //

 // DETAILS : This class implement the WH_CBT Windows hook mechanism.

 //           From MSDN, Dino Esposito.

 //           WindowCreate, WindowDestroy and WindowActivate user events.

 //

 //-----------------------------------------------------------------------------

 using System;

 using System.Text;

 using System.Runtime.InteropServices;

 namespace CodeProject.Win32API.Hook

 {

 	///////////////////////////////////////////////////////////////////////

 	#region Enum CbtHookAction

 	/// <summary>

 	/// CBT hook actions.

 	/// </summary>

 	internal enum CbtHookAction : int

 	{

 		HCBT_MOVESIZE = 0,

 		HCBT_MINMAX = 1,

 		HCBT_QS = 2,

 		HCBT_CREATEWND = 3,

 		HCBT_DESTROYWND = 4,

 		HCBT_ACTIVATE = 5,

 		HCBT_CLICKSKIPPED = 6,

 		HCBT_KEYSKIPPED = 7,

 		HCBT_SYSCOMMAND = 8,

 		HCBT_SETFOCUS = 9

 	}

 	#endregion

 	///////////////////////////////////////////////////////////////////////

 	#region Class CbtEventArgs

 	/// <summary>

 	/// Class used for WH_CBT hook event arguments.

 	/// </summary>

 	public class CbtEventArgs : EventArgs

 	{

 		/// wParam parameter.

 		public IntPtr wParam;

 		/// lParam parameter.

 		public IntPtr lParam;

 		/// Window class name.

 		public string className;

 		/// True if it is a dialog window.

 		public bool IsDialog;

 		internal CbtEventArgs(IntPtr wParam, IntPtr lParam)

 		{

 			// cache the parameters

 			this.wParam = wParam;

 			this.lParam = lParam;

 			// cache the window's class name

 			StringBuilder sb = new StringBuilder();

 			sb.Capacity = 256;

 			USER32.GetClassName(wParam, sb, 256);

 			className = sb.ToString();

 			IsDialog = (className == "#32770");

 		}

 	}

 	#endregion

 	///////////////////////////////////////////////////////////////////////

 	#region Class CbtHook

 	/// <summary>

 	/// Class to expose the windows WH_CBT hook mechanism.

 	/// </summary>

 	public class CbtHook : WindowsHook

 	{

 		/// <summary>

 		/// WH_CBT hook delegate method.

 		/// </summary>

 		public delegate void CbtEventHandler(object sender, CbtEventArgs e);

 		/// <summary>

 		/// WH_CBT create event.

 		/// </summary>

 		public event CbtEventHandler WindowCreate;

 		/// <summary>

 		/// WH_CBT destroy event.

 		/// </summary>

 		public event CbtEventHandler WindowDestroye;

 		/// <summary>

 		/// WH_CBT activate event.

 		/// </summary>

 		public event CbtEventHandler WindowActivate;

 		/// <summary>

 		/// Construct a WH_CBT hook.

 		/// </summary>

 		public CbtHook() : base(HookType.WH_CBT)

 		{

 			this.HookInvoke += new HookEventHandler(CbtHookInvoked);

 		}

 		/// <summary>

 		/// Construct a WH_CBT hook giving a hook filter delegate method.

 		/// </summary>

 		/// <param name="func">Hook filter event.</param>

 		public CbtHook(HookProc func) : base(HookType.WH_CBT, func)

 		{

 			this.HookInvoke += new HookEventHandler(CbtHookInvoked);

 		}

 		// handles the hook event

 		private void CbtHookInvoked(object sender, HookEventArgs e)

 		{

 			// handle hook events (only a few of available actions)

 			switch ((CbtHookAction)e.code)

 			{

 				case CbtHookAction.HCBT_CREATEWND:

 					HandleCreateWndEvent(e.wParam, e.lParam);

 					break;

 				case CbtHookAction.HCBT_DESTROYWND:

 					HandleDestroyWndEvent(e.wParam, e.lParam);

 					break;

 				case CbtHookAction.HCBT_ACTIVATE:

 					HandleActivateEvent(e.wParam, e.lParam);

 					break;

 			}

 			return;

 		}

 		// handle the CREATEWND hook event

 		private void HandleCreateWndEvent(IntPtr wParam, IntPtr lParam)

 		{

 			if (WindowCreate != null)

 			{

 				CbtEventArgs e = new CbtEventArgs(wParam, lParam);

 				WindowCreate(this, e);

 			}

 		}

 		// handle the DESTROYWND hook event

 		private void HandleDestroyWndEvent(IntPtr wParam, IntPtr lParam)

 		{

 			if (WindowDestroye != null)

 			{

 				CbtEventArgs e = new CbtEventArgs(wParam, lParam);

 				WindowDestroye(this, e);

 			}

 		}

 		// handle the ACTIVATE hook event

 		private void HandleActivateEvent(IntPtr wParam, IntPtr lParam)

 		{

 			if (WindowActivate != null)

 			{

 				CbtEventArgs e = new CbtEventArgs(wParam, lParam);

 				WindowActivate(this, e);

 			}

 		}

 	}

 	#endregion

 }