C# 实现全局钩子

1  首先倒入所需要的windows函数，主要有三个，SetWindowsHookEX用来安装钩子，UnhookWindowsHookEX用来卸载钩子以及CallNextHookEX用来将hook信息传递到链表中下一个hook处理过程。

2  在安装全局钩子的时候，我们就要做替换了，将WH_MOUSE和WH_KEYBORAD分别换成WH_MOUSE_LL和WH_KEYBORAD_LL： 

//SetWindowsHookEX 用于安装钩子
[DllImport(\"user32.dll\",CharSetCharSet=CharSet.Auto,  　　CallingConventionCallingConvention=CallingConvention.StdCall,SetLastError=true)]  　　private static extern int SetWindowsHookEx(  　　intidHook,  　　HookProclpfn,  　　IntPtrhMod,  　　intdwThreadId);  

//UnHookWindowsHookEX 用于卸载钩子　　 　　
[DllImport(\"user32.dll\",CharSetCharSet=CharSet.Auto,  　　CallingConventionCallingConvention=CallingConvention.StdCall,SetLastError=true)]  　　private static extern int UnhookWindowsHookEx(intidHook);  　　

//CallNextHookEX 用于将hook信息传递到链表中下一个hook处理过程 　　
[DllImport(\"user32.dll\",CharSetCharSet=CharSet.Auto,  　　CallingConventionCallingConvention=CallingConvention.StdCall)]  　　private static extern int CallNextHookEx(  　　intidHook,  　　intnCode,  　　intwParam,  　　IntPtrlParam); 


//installhook  　其中第一个参数WH_MOUSE_LL原来是WH_MOUSE
hMouseHook=SetWindowsHookEx(WH_MOUSE_LL,MouseHookProcedure,Marshal.GetHINSTANCE(Assembly.GetExecutingAssembly().GetModules()[0]),0);  
　　 　　
//installhook    其中第一个参数WH_KEYBOARD_LL原来是WH_KEYBORAD
hKeyboardHook=SetWindowsHookEx(WH_KEYBOARD_LL,KeyboardHookProcedure,Marshal.GetHINSTANCE(Assembly.GetExecutingAssembly().GetModules()[0]),  　　0);

//下面是关于鼠标和键盘的两个Callback函数： 
　private int MouseHookProc(int nCode, int wParam, IntPtr lParam)  　　
  {  　　// if ok and someone listens to our events  　　
      if ((nCode >= 0) && (OnMouseActivity != null))  　　
      {  　　
         //Marshall the data from callback.  　　
           MouseLLHookStruct mouseHookStruct = (MouseLLHookStruct)Marshal.　　PtrToStructure(lParam, typeof(MouseLLHookStruct));  　　 　　
         //detect button clicked  　　
           MouseButtons button = MouseButtons.None;  　　
           short mouseDelta = 0;