c# 钩子类

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Runtime.InteropServices;
using System.Text; namespace WindowsFormsApplication1
{
/// <summary>
/// 键盘Hook管理类 /// </summary>
public class KeyboardHookLib
{
private const int WH_KEYBOARD_LL = ; //键盘 //键盘处理事件委托.
private delegate int HookHandle(int nCode, int wParam, IntPtr lParam); //客户端键盘处理事件
public delegate void ProcessKeyHandle(HookStruct param, out bool handle); //接收SetWindowsHookEx返回值
private static int _hHookValue = ; //勾子程序处理事件
private HookHandle _KeyBoardHookProcedure; //Hook结构
[StructLayout(LayoutKind.Sequential)]
public class HookStruct
{
public int vkCode;
public int scanCode;
public int flags;
public int time;
public int dwExtraInfo;
} //设置钩子
[DllImport("user32.dll")]
private static extern int SetWindowsHookEx(int idHook, HookHandle lpfn, IntPtr hInstance, int threadId); //取消钩子
[DllImport("user32.dll", CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall)]
private static extern bool UnhookWindowsHookEx(int idHook); //调用下一个钩子
[DllImport("user32.dll")]
private static extern int CallNextHookEx(int idHook, int nCode, int wParam, IntPtr lParam); //获取当前线程ID
[DllImport("kernel32.dll")]
private static extern int GetCurrentThreadId(); //Gets the main module for the associated process.
[DllImport("kernel32.dll")]
private static extern IntPtr GetModuleHandle(string name); private IntPtr _hookWindowPtr = IntPtr.Zero; //构造器
public KeyboardHookLib() { } //外部调用的键盘处理事件
private static ProcessKeyHandle _clientMethod = null; /// <summary>
/// 安装勾子
/// </summary>
/// <param name="hookProcess">外部调用的键盘处理事件</param>
public void InstallHook(ProcessKeyHandle clientMethod)
{
_clientMethod = clientMethod; // 安装键盘钩子
if (_hHookValue == )
{
_KeyBoardHookProcedure = new HookHandle(GetHookProc); _hookWindowPtr = GetModuleHandle(Process.GetCurrentProcess().MainModule.ModuleName); _hHookValue = SetWindowsHookEx(
WH_KEYBOARD_LL,
_KeyBoardHookProcedure,
_hookWindowPtr,
); //如果设置钩子失败.
if (_hHookValue == ) UninstallHook();
}
} //取消钩子事件
public void UninstallHook()
{
if (_hHookValue != )
{
bool ret = UnhookWindowsHookEx(_hHookValue);
if (ret) _hHookValue = ;
}
} //钩子事件内部调用,调用_clientMethod方法转发到客户端应用。
private static int GetHookProc(int nCode, int wParam, IntPtr lParam)
{
if (nCode >= )
{
//转换结构
HookStruct hookStruct = (HookStruct)Marshal.PtrToStructure(lParam, typeof(HookStruct)); if (_clientMethod != null)
{
bool handle = false;
//调用客户提供的事件处理程序。
_clientMethod(hookStruct, out handle);
if (handle) return ; //1:表示拦截键盘,return 退出
}
}
return CallNextHookEx(_hHookValue, nCode, wParam, lParam);
} }
}

//钩子管理类
private KeyboardHookLib _keyBoardHook = null; //安装钩子
private void button5_Click(object sender, EventArgs e)
{
_keyBoardHook = new KeyboardHookLib();
_keyBoardHook.InstallHook(this.KeyPress); } //取消钩子
private void button6_Click(object sender, EventArgs e)
{
if (_keyBoardHook != null) _keyBoardHook.UninstallHook();
} public void KeyPress(KeyboardHookLib.HookStruct hookStruct, out bool handle)
{
handle = false; //预设不拦截任何键 if (hookStruct.vkCode == ) // 截获左win(开始菜单键)
{
handle = true;
} if (hookStruct.vkCode == )// 截获右win
{
handle = true;
} //截获Ctrl+Esc
if (hookStruct.vkCode == (int)Keys.Escape && (int)Control.ModifierKeys == (int)Keys.Control)
{
handle = true;
} //截获alt+f4
if (hookStruct.vkCode == (int)Keys.F4 && (int)Control.ModifierKeys == (int)Keys.Alt)
{
handle = true;
} //截获alt+tab
if (hookStruct.vkCode == (int)Keys.Tab && (int)Control.ModifierKeys == (int)Keys.Alt)
{
handle = true;
} //截获F1
if (hookStruct.vkCode == (int)Keys.F1)
{
handle = true;
} //截获Ctrl+Alt+Delete
if ((int)Control.ModifierKeys == (int)Keys.Control + (int)Keys.Alt + (int)Keys.Delete)
{
handle = true;
} //如果键A~Z
if (hookStruct.vkCode >= (int)Keys.A && hookStruct.vkCode <= (int)Keys.Z)
{
//挡掉G键，想要挡掉哪些键就把下面的G换成那个要挡掉的键，同理可以挡多个
if (hookStruct.vkCode == (int)Keys.G)
hookStruct.vkCode = (int)Keys.None; //设键为0 handle = true;
} Keys key = (Keys)hookStruct.vkCode;
label1.Text = "你按下:" + (key == Keys.None ? "None" : key.ToString());
}