钩子的简单例子



界面

后台代码

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace TestHook
{
    public partial class Form1 : Form
    {
        #region 第一步:声明API函数
        //使用钩子，需要使用WindowsAPI函数，所以要先声明这些API函数。
        // 安装钩子
        [DllImport("user32.dll", CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall)]
        public static extern int SetWindowsHookEx(int idHook, HookProc lpfn, IntPtr hInstance, int threadId);

        // 卸载钩子
        [DllImport("user32.dll", CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall)]
        public static extern bool UnhookWindowsHookEx(int idHook);

        // 继续下一个钩子
        [DllImport("user32.dll", CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall)]
        public static extern int CallNextHookEx(int idHook, int nCode, Int32 wParam, IntPtr lParam);

        // 取得当前线程编号
        [DllImport("kernel32.dll")]
        static extern int GetCurrentThreadId();

        //// 全局钩子
        //[DllImport("user32.dll", CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall)]
        //SetWindowsHookEx( 13, KeyboardHookProcedure, Marshal.GetHINSTANCE(Assembly.GetExecutingAssembly().GetModules()[0]),0)

        #endregion

        #region 第二步：声明，定义委托
        public delegate int HookProc(int nCode, Int32 wParam, IntPtr lParam);

        static int hKeyboardHook = 0;//如果hKeyboardHook不为0则说明钩子安装成功

        HookProc KeyboardHookProcedure;
        #endregion
        #region 第三步：编写钩子子程
        //钩子子程就是钩子所要做的事情。

        private int KeyboardHookProc(int nCode, Int32 wParam, IntPtr IParam)
        {
            if (nCode >= 0)
            {
                textBox1.Text = "hello,哈哈哈哈";
                return 1;
            }
            return CallNextHookEx(hKeyboardHook, nCode, wParam, IParam);
        }
        #endregion

        #region 第四步：正式启用钩子
        //钩子安装
        public void HookStart()
        {
            if (hKeyboardHook == 0)//如果hKeyboardHook==0,钩子安装失败
            {
                //创建HookProc实例
                KeyboardHookProcedure = new HookProc(KeyboardHookProc);
                //设置线程钩子
                hKeyboardHook = SetWindowsHookEx(2, KeyboardHookProc, IntPtr.Zero, GetCurrentThreadId());

                if (hKeyboardHook == 0)
                {
                    //终止钩子
                    throw new Exception("安装钩子失败");
                }
            }
        }

        //钩子卸载
        public void HookStop()
        {
            bool retKeyboard = true;
            if (hKeyboardHook != 0)
            {
                retKeyboard = UnhookWindowsHookEx(hKeyboardHook);
                hKeyboardHook = 0;
            }
            if (!retKeyboard)
                throw new Exception("钩子卸载失败");

        }
        #endregion

        public Form1()
        {
            InitializeComponent();
        }

     

        private void button1_Click(object sender, EventArgs e)
        {
            this.HookStart();
        }

        private void button2_Click(object sender, EventArgs e)
        {
            this.HookStop();
        }

        public struct MSG
        {
            public Point p;
            public IntPtr HWnd;
            public uint wHitTestCode;
            public int dwExtraInfo;
        }

        public struct KeyMSG
        {
            public int vkCode;
            public int scanCode;
            public int flags;
            public int time;
            public int dwExtraInfo;
        }

        //        MSG m = (MSG)Marshal.PtrToStructure(lParam, typeof(MSG));
        //        KeyMSG m = (KeyMSG)Marshal.PtrToStructure(lParam, typeof(KeyMSG));
        //        // 按下的键
        //        Keys keyData = (Keys)wParam;
        //if(lParam.ToInt32() > 0)        
        //{
        //     // 键盘按下
        //}
        //if(lParam.ToInt32() < 0)        
        //{
        //     // 键盘抬起
        //}

    }
}