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

// 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

}