如何用C#作全局（也就是系统）键盘钩子

public class Win32Hook
 {    [DllImport("kernel32")]
     public static extern int GetCurrentThreadId();    [DllImport( "user32", 
 CharSet=CharSet.Auto,CallingConvention=CallingConvention.StdCall)]
     public static extern int  SetWindowsHookEx(
         HookType idHook,
         HOOKPROC lpfn,
         int hmod,
         int dwThreadId);    public enum HookType
     {
         WH_KEYBOARD = 2
     }
     
 public delegate int HOOKPROC(int nCode, int wParam, int    lParam);    public void SetHook()
     {
         // set the keyboard hook
         SetWindowsHookEx(HookType.WH_KEYBOARD,
             new HOOKPROC(this.MyKeyboardProc),
             0,
             GetCurrentThreadId());
     }    public int MyKeyboardProc(int nCode, int wParam, int lParam)
     {
         //在这里放置你的处理代码        return 0;
     }
 }

使用方法
可以在Form的构造函数里放入

Win32Hook hook = new Win32Hook();
 hook.SetHook();