本文讲解了在C#中使用钩子技术处理消息的方法。

1、声明钩子函数代理：

public delegate IntPtr HookProc(int nCode, IntPtr wParam, IntPtr lParam);

2、声明API函数：

[DllImport("user32.dll", CharSet=CharSet.Auto)] public static extern IntPtr SetWindowsHookEx(int hookid, HookProc pfnhook, IntPtr hinst, int threadid);

[DllImport("user32.dll", CharSet=CharSet.Auto, ExactSpelling=true)] public static extern bool UnhookWindowsHookEx(IntPtr hhook);

[DllImport("user32.dll", CharSet=CharSet.Auto, ExactSpelling=true)] public static extern IntPtr CallNextHookEx(IntPtr hhook, int code, IntPtr wparam, IntPtr lparam);

[DllImport("kernel32.dll", ExactSpelling=true, CharSet=CharSet.Auto)] public static extern int GetCurrentThreadId();

public const int WH_MSGFILTER = -1;

3、写你自己的HookProc代理实现方法，如MyHookProc

public IntPtr MyHookProc(int nCode, IntPtr wParam, IntPtr lParam) { //...你的代码 return CallNextHookEx(iHookHandle, code, wparam, lparam);}

4、为你的类声明一个Hook Handle和非托管的钩子线程地址：

private IntPtr _iHookHandle=IntPtr.Zero; private GCHandle _hookProcHandle;

5、在合适的地方安装你的钩子

HookProc hookProc = new HookProc(MyHookProc); _hookProcHandle = GCHandle.Alloc(hookProc); iHookHandle = SetWindowsHookEx(WH_MSGFILTER, hookProc,IntPtr.Zero, .GetCurrentThreadId()); if (iHookHandle == IntPtr.Zero) throw new System.Exception("没有足够权限安装钩子！");

6、在合适的地方卸载你的钩子

if (iHookHandle!=IntPtr.Zero)UnhookWindowsHookEx(iHookHandle); _hookProcHandle.Free(); iHookHandle = IntPtr.Zero;