[转]C#中使用消息钩子的方法

本文转自：http://www.xbjy.com/D_info.aspx?ID=9284

原文如下：

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1、声明一个钩子函数代理：

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;