c#钩子程序键盘事件监听（拦截系统组合键）WebBrowser浏览器控件

1.什么是钩子程序

hook（钩子）是windows提供的一种消息处理机制平台，是指在程序正常运行中接受信息之前预先启动的函数，用来检查和修改传给该程序的信息，（钩子）实际上是一个处理消息的程序段，通过系统调用，把它挂入系统。每当特定的消息发出，在没有到达目的窗口前，钩子程序就先捕获该消息，亦即钩子函数先得到控制权。这时钩子函数即可以加工处理（改变）该消息，也可以不作处理而继续传递该消息，还可以强制结束消息的传递(return)。

运行下面的程序案例需注意，程序会全屏展示，并且拦截所有系统组合键（除ctrl+alt+del），在程序菜单栏可退出。

2.钩子程序的主要代码

using System;
using System.Diagnostics;
using System.Runtime.InteropServices;
using System.Windows.Forms;
using static WindowsFormsApplication1.Win32Api;
namespace WindowsFormsApplication1
{
    /**
     * c#钩子程序 键盘监控(拦截系统组合键)
     * */
    public class Win32Api
    {
        #region 常数和结构
        public const int WM_KEYDOWN = 0x100;

        public const int WM_KEYUP = 0x101;

        public const int WM_SYSKEYDOWN = 0x104;

        public const int WM_SYSKEYUP = 0x105;

        public const int WH_KEYBOARD_LL = 13;

        [StructLayout(LayoutKind.Sequential)] //声明键盘钩子的封送结构类型 

        public class KeyboardHookStruct
        {
            public int vkCode; //表示一个在1到254间的虚似键盘码 
            public int scanCode; //表示硬件扫描码 
            public int flags;
            public int time;
            public int dwExtraInfo;
        }

        #endregion
        #region Api

        public delegate int HookProc(int nCode, Int32 wParam, IntPtr lParam);

        //安装钩子的函数 
        [DllImport("user32.dll", CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall)]
        public static extern int SetWindowsHookEx(int idHook, HookProc lpfn, IntPtr hInstance, int threadId);

        //卸下钩子的函数 
        [DllImport("user32.dll", CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall)]
        public static extern bool UnhookWindowsHookEx(int idHook);

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

        [DllImport("user32")]
        public static extern int ToAscii(int uVirtKey, int uScanCode, byte[] lpbKeyState, byte[] lpwTransKey, int fuState);

        [DllImport("user32")]
        public static extern int GetKeyboardState(byte[] pbKeyState);

        [DllImport("kernel32.dll", CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall)]
        public static extern IntPtr GetModuleHandle(string lpModuleName);

        #endregion
    }

    public class KeyboardHook
    {
        int hHook;

        Win32Api.HookProc KeyboardHookDelegate;

        public event KeyEventHandler OnKeyDownEvent;

        public event KeyEventHandler OnKeyUpEvent;

        public event KeyPressEventHandler OnKeyPressEvent;

        public KeyboardHook() { }

        /**
         * 设置钩子
         * */
        public void SetHook()
        {
            KeyboardHookDelegate = new Win32Api.HookProc(KeyboardHookProc);
            Process cProcess = Process.GetCurrentProcess();
            ProcessModule cModule = cProcess.MainModule;
            var mh = Win32Api.GetModuleHandle(cModule.ModuleName);
            hHook = Win32Api.SetWindowsHookEx(Win32Api.WH_KEYBOARD_LL, KeyboardHookDelegate, mh, 0);
        }

        /**
         * 卸载钩子
         * */
        public void UnHook()
        {
            Win32Api.UnhookWindowsHookEx(hHook);
        }

        /**
         * 拦截按键
         * nCode参数是钩子代码，钩子子程使用这个参数来确定任务，这个参数的值依赖于Hook类型。
         * wParam和lParam参数包含了消息信息，我们可以从中提取需要的信息。
         * */
        private int KeyboardHookProc(int nCode, Int32 wParam, IntPtr lParam)
        {
            if (nCode >= 0)
            {
                KeyboardHookStruct kbh = (KeyboardHookStruct)Marshal.PtrToStructure(lParam, typeof(KeyboardHookStruct));
                // 截获左win(开始菜单键)
                if (kbh.vkCode == 91)
                {
                    return 1;
                }
                // 截获右win
                if (kbh.vkCode == 92)
                {
                    return 1;
                }
                //截获Ctrl+Esc
                if (kbh.vkCode == (int)Keys.Escape && (int)Control.ModifierKeys == (int)Keys.Control)
                {
                    return 1;
                }
                //截获alt+f4
                if (kbh.vkCode == (int)Keys.F4 && (int)Control.ModifierKeys == (int)Keys.Alt)
                {
                    return 1;
                }
                //截获alt+tab
                if (kbh.vkCode == (int)Keys.Tab && (int)Control.ModifierKeys == (int)Keys.Alt)
                {
                    return 1;
                }
                //截获Ctrl+Shift+Esc
                if (kbh.vkCode == (int)Keys.Escape && (int)Control.ModifierKeys == (int)Keys.Control + (int)Keys.Shift)
                {
                    return 1;
                }
                //截获alt+空格
                if (kbh.vkCode == (int)Keys.Space && (int)Control.ModifierKeys == (int)Keys.Alt)
                {
                    return 1;
                }
                //截获F1
                if (kbh.vkCode == 241)
                {
                    return 1;
                }
                //截获Ctrl+Alt+Delete
                if ((int)Control.ModifierKeys == (int)Keys.Control + (int)Keys.Alt + (int)Keys.Delete)      
                {
                    return 1;
                }
            }
            return Win32Api.CallNextHookEx(hHook, nCode, wParam, lParam);
        }
    }
}

3.窗体类主要代码：

using System;
using System.Windows.Forms;
/**
 * 命名空间，类似于java中的import
 * */
namespace WindowsFormsApplication1
{
    static class Program
    {
        /// <summary>
        /// 应用程序的主入口点。
        /// </summary>
        [STAThread]
        static void Main()
        {
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);
            Application.Run(new Form1());
        }
    }
}

4.窗体样式主要代码：

using System;
using System.Windows.Forms;
namespace WindowsFormsApplication1
{
    partial class Form1
    {
        /// <summary>
        /// 必需的设计器变量。
        /// </summary>
        private System.ComponentModel.IContainer components = null;

        /// <summary>
        /// 清理所有正在使用的资源。
        /// </summary>
        /// <param name="disposing">如果应释放托管资源，为 true；否则为 false。</param>
        protected override void Dispose(bool disposing)
        {
            if (disposing && (components != null))
            {
                components.Dispose();
            }
            base.Dispose(disposing);
        }

        #region Windows 窗体设计器生成的代码

        /// <summary>
        /// 设计器支持所需的方法 - 不要修改
        /// 使用代码编辑器修改此方法的内容。
        /// </summary>
        private void InitializeComponent()
        {
            this.menuStrip1 = new System.Windows.Forms.MenuStrip();
            this.菜单ToolStripMenuItem = new System.Windows.Forms.ToolStripMenuItem();
            this.退出程序ToolStripMenuItem = new System.Windows.Forms.ToolStripMenuItem();
            this.考试须知ToolStripMenuItem = new System.Windows.Forms.ToolStripMenuItem();
            this.webBrowser1 = new System.Windows.Forms.WebBrowser();
            this.menuStrip1.SuspendLayout();
            this.SuspendLayout();
            // 
            // menuStrip1
            // 
            this.menuStrip1.Items.AddRange(new System.Windows.Forms.ToolStripItem[] {
            this.菜单ToolStripMenuItem,
            this.考试须知ToolStripMenuItem});
            this.menuStrip1.Location = new System.Drawing.Point(0, 0);
            this.menuStrip1.Name = "menuStrip1";
            this.menuStrip1.Size = new System.Drawing.Size(893, 25);
            this.menuStrip1.TabIndex = 0;
            this.menuStrip1.Text = "menuStrip1";
            // 
            // 菜单ToolStripMenuItem
            // 
            this.菜单ToolStripMenuItem.DropDownItems.AddRange(new System.Windows.Forms.ToolStripItem[] {
            this.退出程序ToolStripMenuItem});
            this.菜单ToolStripMenuItem.Name = "菜单ToolStripMenuItem";
            this.菜单ToolStripMenuItem.Size = new System.Drawing.Size(44, 21);
            this.菜单ToolStripMenuItem.Text = "菜单";
            // 
            // 退出程序ToolStripMenuItem
            // 
            this.退出程序ToolStripMenuItem.Name = "退出程序ToolStripMenuItem";
            this.退出程序ToolStripMenuItem.Size = new System.Drawing.Size(124, 22);
            this.退出程序ToolStripMenuItem.Text = "退出程序";
            this.退出程序ToolStripMenuItem.Click += new System.EventHandler(this.退出程序ToolStripMenuItem_Click);
            // 
            // 考试须知ToolStripMenuItem
            // 
            this.考试须知ToolStripMenuItem.Name = "考试须知ToolStripMenuItem";
            this.考试须知ToolStripMenuItem.Size = new System.Drawing.Size(68, 21);
            this.考试须知ToolStripMenuItem.Text = "考试须知";
            this.考试须知ToolStripMenuItem.Click += new System.EventHandler(this.考试须知ToolStripMenuItem_Click);
            // 
            // webBrowser1 属性设置
            // 
            this.webBrowser1.Dock = System.Windows.Forms.DockStyle.Fill;
            this.webBrowser1.Location = new System.Drawing.Point(0, 25);
            this.webBrowser1.MinimumSize = new System.Drawing.Size(20, 20);
            this.webBrowser1.Name = "webBrowser1";
            this.webBrowser1.Size = new System.Drawing.Size(893, 286);
            this.webBrowser1.TabIndex = 1;

            /**
             * 设置 WebBrowser 容器默认请求的ip地址
             * */
            this.webBrowser1.Navigate("http://www.baidu.com");

            // 
            // Form1
            // 
            this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 12F);
            this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
            this.ClientSize = new System.Drawing.Size(893, 311);
            this.Controls.Add(this.webBrowser1);
            this.Controls.Add(this.menuStrip1);
            this.FormBorderStyle = System.Windows.Forms.FormBorderStyle.None;
            this.MainMenuStrip = this.menuStrip1;
            this.Name = "Form1";
            this.ShowInTaskbar = false;
            this.Text = "Form1";
            this.TopMost = true;
            this.WindowState = System.Windows.Forms.FormWindowState.Maximized;//窗体最大化
            this.FormClosing += new System.Windows.Forms.FormClosingEventHandler(this.Form1_FormClosing);
            this.Load += new System.EventHandler(this.Form1_Load);
            this.menuStrip1.ResumeLayout(false);
            this.menuStrip1.PerformLayout();
            this.ResumeLayout(false);
            this.PerformLayout();

        }

        #endregion
        /**
         * 定义菜单
         * */
        private MenuStrip menuStrip1;
        /**
         * 定义菜单按钮
         * */
        private ToolStripMenuItem 菜单ToolStripMenuItem;
        private ToolStripMenuItem 退出程序ToolStripMenuItem;
        private ToolStripMenuItem 考试须知ToolStripMenuItem;

        /**
         * 定义WebBrowser容器
         * */
        private WebBrowser webBrowser1;
    }
}

5.窗体事件的主要代码：

using System;
using System.Diagnostics;
using System.Windows.Forms;
namespace WindowsFormsApplication1
{
    /**
     * 窗体类
     * */
    public partial class Form1 : Form
    {
        public Form1()
        {
            /**
             * 容器初始化
             * */
            InitializeComponent();
        }
        /**
         * 定义钩子对象
         * */
        KeyboardHook kh;

        /**
         * 窗体加载时启动 winfrom 钩子
         **/
        private void Form1_Load(object sender, EventArgs e)
        {
            kh = new KeyboardHook();
            kh.SetHook();
        }
        
        /**
         * 键盘事件监听
         * */
        void kh_OnKeyDownEvent(object sender, KeyEventArgs e)
        {
            
        }

        /**
         * 窗体关闭
         * */
        private void Form1_FormClosing(object sender, FormClosingEventArgs e)
        {
            kh.UnHook();
        }

        /**
         * 退出程序
         * */
        private void 退出程序ToolStripMenuItem_Click(object sender, EventArgs e)
        {
            Process.GetCurrentProcess().Kill();
        }

        private void 考试须知ToolStripMenuItem_Click(object sender, EventArgs e)
        {
            MessageBox.Show("考生请注意：作弊者，格杀勿论，不留余地~");
        }
    }
}