键盘 钩子 的代码

转载一篇关于 键盘 钩子的。。。代码。。。

using System;
using System.Text;
using System.Runtime.InteropServices;
using System.Reflection;
using System.Windows.Forms;
 
namespace MouseKeyboardLibrary
{
 
    /// <summary>
    /// Abstract base class for Mouse and Keyboard hooks
    /// </summary>
    public abstract class GlobalHook
    {
 
        #region Windows API Code
 
        [StructLayout(LayoutKind.Sequential)]
        protected class POINT
        {
            public int x;
            public int y;
        }
 
        [StructLayout(LayoutKind.Sequential)]
        protected class MouseHookStruct
        {
            public POINT pt;
            public int hwnd;
            public int wHitTestCode;
            public int dwExtraInfo;
        }
 
        [StructLayout(LayoutKind.Sequential)]
        protected class MouseLLHookStruct
        {
            public POINT pt;
            public int mouseData;
            public int flags;
            public int time;
            public int dwExtraInfo;
        }
 
        [StructLayout(LayoutKind.Sequential)]
        protected class KeyboardHookStruct
        {
            public int vkCode;
            public int scanCode;
            public int flags;
            public int time;
            public int dwExtraInfo;
        }
 
        [DllImport("user32.dll", CharSet = CharSet.Auto,
           CallingConvention = CallingConvention.StdCall, SetLastError = true)]
        protected static extern int SetWindowsHookEx(
            int idHook,
            HookProc lpfn,
            IntPtr hMod,
            int dwThreadId);
 
        [DllImport("user32.dll", CharSet = CharSet.Auto,
            CallingConvention = CallingConvention.StdCall, SetLastError = true)]
        protected static extern int UnhookWindowsHookEx(int idHook);
 
 
        [DllImport("user32.dll", CharSet = CharSet.Auto,
             CallingConvention = CallingConvention.StdCall)]
        protected static extern int CallNextHookEx(
            int idHook,
            int nCode,
            int wParam,
            IntPtr lParam);
 
        [DllImport("user32")]
        protected static extern int ToAscii(
            int uVirtKey,
            int uScanCode,
            byte[] lpbKeyState,
            byte[] lpwTransKey,
            int fuState);
 
        [DllImport("user32")]
        protected static extern int GetKeyboardState(byte[] pbKeyState);
 
        [DllImport("user32.dll", CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall)]
        protected static extern short GetKeyState(int vKey);
 
        protected delegate int HookProc(int nCode, int wParam, IntPtr lParam);
 
        protected const int WH_MOUSE_LL = 14;
        protected const int WH_KEYBOARD_LL = 13;
 
        protected const int WH_MOUSE = 7;
        protected const int WH_KEYBOARD = 2;
        protected const int WM_MOUSEMOVE = 0x200;
        protected const int WM_LBUTTONDOWN = 0x201;
        protected const int WM_RBUTTONDOWN = 0x204;
        protected const int WM_MBUTTONDOWN = 0x207;
        protected const int WM_LBUTTONUP = 0x202;
        protected const int WM_RBUTTONUP = 0x205;
        protected const int WM_MBUTTONUP = 0x208;
        protected const int WM_LBUTTONDBLCLK = 0x203;
        protected const int WM_RBUTTONDBLCLK = 0x206;
        protected const int WM_MBUTTONDBLCLK = 0x209;
        protected const int WM_MOUSEWHEEL = 0x020A;
        protected const int WM_KEYDOWN = 0x100;
        protected const int WM_KEYUP = 0x101;
        protected const int WM_SYSKEYDOWN = 0x104;
        protected const int WM_SYSKEYUP = 0x105;
 
        protected const byte VK_SHIFT = 0x10;
        protected const byte VK_CAPITAL = 0x14;
        protected const byte VK_NUMLOCK = 0x90;
 
        protected const byte VK_LSHIFT = 0xA0;
        protected const byte VK_RSHIFT = 0xA1;
        protected const byte VK_LCONTROL = 0xA2;
        protected const byte VK_RCONTROL = 0x3;
        protected const byte VK_LALT = 0xA4;
        protected const byte VK_RALT = 0xA5;
 
        protected const byte LLKHF_ALTDOWN = 0x20;
 
        #endregion
 
        #region Private Variables
 
        protected int _hookType;
        protected int _handleToHook;
        protected bool _isStarted;
        protected HookProc _hookCallback;
 
        #endregion
 
        #region Properties
 
        public bool IsStarted
        {
            get
            {
                return _isStarted;
            }
        }
 
        #endregion
 
        #region Constructor
 
        public GlobalHook()
        {
 
            Application.ApplicationExit += new EventHandler(Application_ApplicationExit);
 
        }
 
        #endregion
 
        #region Methods
 
        public void Start()
        {
 
            if (!_isStarted &&
                _hookType != 0)
            {
 
                // Make sure we keep a reference to this delegate!
                // If not, GC randomly collects it, and a NullReference exception is thrown
                _hookCallback = new HookProc(HookCallbackProcedure);
 
                _handleToHook = SetWindowsHookEx(
                    _hookType,
                    _hookCallback,
                    Marshal.GetHINSTANCE(Assembly.GetExecutingAssembly().GetModules()[0]),
                    0);
 
                // Were we able to sucessfully start hook?
                if (_handleToHook != 0)
                {
                    _isStarted = true;
                }
 
            }
 
        }
 
        public void Stop()
        {
 
            if (_isStarted)
            {
 
                UnhookWindowsHookEx(_handleToHook);
 
                _isStarted = false;
 
            }
 
        }
 
        protected virtual int HookCallbackProcedure(int nCode, Int32 wParam, IntPtr lParam)
        {
            
            // This method must be overriden by each extending hook
            return 0;
 
        }
 
        protected void Application_ApplicationExit(object sender, EventArgs e)
        {
 
            if (_isStarted)
            {
                Stop();
            }
 
        }
 
        #endregion
 
    }
 
}