c# 屏蔽快捷键的实现示例-C#/.NET问题

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前言

有时候开发会遇到这样一个需求，软件需要屏蔽用户的组合快捷键或某些按键，避免强制退出软件，防止勿操作等。

原理

1、要实现组合键，按键拦截，需要用到user32.dll中的SetWindowsHookEx。

2、要拦截ctrl+alt+del，需要使用ntdll.dll的ZwSuspendProcess函数挂起winlogon程序，退出之后使用ZwResumeProcess恢复winlogon程序。

3、软件需要开启topMost，以及全屏，否则离开软件则拦截无效。

4、如果要实现热键监听（非焦点拦截），则需要用到user32.dll的RegisterHotKey以及UnregisterHotKey。

实现

1、Program类


using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Runtime.InteropServices;
using System.Windows.Forms;

namespace LockForm
{
 static class Program
 {
  /// <summary>
  /// 应用程序的主入口点。
  /// </summary>
  [STAThread]
  static void Main()
  {
   Application.EnableVisualStyles();
   Application.SetCompatibleTextRenderingDefault(false);
   SuspendWinLogon();
   Application.Run(new Form1());
   ResumeWinLogon();
  }

  [DllImport("ntdll.dll")]
  public static extern int ZwSuspendProcess(IntPtr ProcessId);
  [DllImport("ntdll.dll")]
  public static extern int ZwResumeProcess(IntPtr ProcessId);

  private static void SuspendWinLogon()
  {
   Process[] pc = Process.GetProcessesByName("winlogon");
   if (pc.Length > 0)
   {
    ZwSuspendProcess(pc[0].Handle);
   }
  }

  private static void ResumeWinLogon()
  {
   Process[] pc = Process.GetProcessesByName("winlogon");
   if (pc.Length > 0)
   {
    ZwResumeProcess(pc[0].Handle);
   }
  }
 }
}

2、Form1类


using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Diagnostics;
using System.Drawing;
using System.Runtime.InteropServices;
using System.Text;
using System.Windows.Forms;

namespace LockForm
{
 public partial class Form1 : Form
 {
  public Form1()
  {
   InitializeComponent();
  }

  private void button1_Click(object sender, EventArgs e)
  {
   if (textBox1.Text == "123")
   {
    Application.ExitThread();
   }
   else
   {
    webBrowser1.Navigate(textBox1.Text);
   }
  }

  private void Form1_Load(object sender, EventArgs e)
  {
   //webBrowser1.Navigate("https://baidu.com");
   HookStart();
   //this.TopMost = false;
   //SuspendWinLogon();
  }

  private void webBrowser1_NewWindow(object sender, CancelEventArgs e)
  {
   e.Cancel = true;
   webBrowser1.Navigate(webBrowser1.Document.ActiveElement.GetAttribute("href"));
  }

  private void button3_Click(object sender, EventArgs e)
  {
   webBrowser1.GoBack();
  }

  private void button2_Click(object sender, EventArgs e)
  {
   webBrowser1.GoForward();
  }

  private void button4_Click(object sender, EventArgs e)
  {
   webBrowser1.GoHome();
  }

  private void webBrowser1_Navigated(object sender, WebBrowserNavigatedEventArgs e)
  {
   textBox1.Text = webBrowser1.Url.ToString();
  }

  private void webBrowser1_Navigating(object sender, WebBrowserNavigatingEventArgs e)
  {

  }

  #region 键盘钩子

  public delegate int HookProc(int nCode, int wParam, IntPtr lParam);//定义全局钩子过程委托，以防被回收（钩子函数原型）
  HookProc KeyBoardProcedure;

  //定义键盘钩子的相关内容，用于截获键盘消息
  static int hHook = 0;//钩子函数的句柄
  public const int WH_KEYBOARD = 13;
  //钩子结构函数
  public struct KeyBoardHookStruct
  {
   public int vkCode;
   public int scanCode;
   public int flags;
   public int time;
   public int dwExtraInfo;

  }
  //安装键盘钩子
  public void HookStart()
  {

   if (hHook == 0)
   {
    //实例化一个HookProc对象
    KeyBoardProcedure = new HookProc(Form1.KeyBoardHookProc);

    //创建线程钩子
    hHook = Win32API.SetWindowsHookEx(WH_KEYBOARD, KeyBoardProcedure, Win32API.GetModuleHandle(Process.GetCurrentProcess().MainModule.ModuleName), 0);

    //如果设置线程钩子失败
    if (hHook == 0)
    {
     HookClear();
    }
   }
  }

  //取消钩子
  public void HookClear()
  {
   bool rsetKeyboard = true;
   if (hHook != 0)
   {
    rsetKeyboard = Win32API.UnhookWindowsHookEx(hHook);
    hHook = 0;
   }
   if (!rsetKeyboard)
   {
    throw new Exception("取消钩子失败!");
   }
  }
  //对截获的键盘操作的处理
  public static int KeyBoardHookProc(int nCode, int wParam, IntPtr lParam)
  {
   if (nCode >= 0)
   {
    KeyBoardHookStruct kbh = (KeyBoardHookStruct)Marshal.PtrToStructure(lParam, typeof(KeyBoardHookStruct));

    if (kbh.vkCode == 91)//截获左边WIN键
    {
     return 1;
    }
    if (kbh.vkCode == 92)//截获右边WIN键
    {
     return 1;
    }
    if (kbh.vkCode == (int)Keys.Escape && (int)Control.ModifierKeys == (int)Keys.Control)//截获Ctrl+ESC键
    {
     return 1;
    }
    if (kbh.vkCode == (int)Keys.Escape && (int)Control.ModifierKeys == (int)Keys.Alt)
    {
     return 1;
    }
    if (kbh.vkCode == (int)Keys.F4 && (int)Control.ModifierKeys == (int)Keys.Alt)//截获ALT+F4
    {
     return 1;
    }
    if (kbh.vkCode == (int)Keys.Tab && (int)Control.ModifierKeys == (int)Keys.Alt)//截获ALT+TAB
    {
     return 1;
    }
    if (kbh.vkCode == (int)Keys.Delete&&(int)Control.ModifierKeys == (int)Keys.Control + (int)Keys.Alt)
    {
     return 1;
    }
    if ( kbh.vkCode == (int) Keys.Escape && (int) Control.ModifierKeys == (int) Keys.Control + (int) Keys.Alt ) /* 截获Ctrl+Shift+Esc */
    {
     return 1;
    }

   }

   return Win32API.CallNextHookEx(hHook, nCode, wParam, lParam);
  }
  #endregion
 }
}

3、声明windows api


//设置钩子
  [DllImport("user32.dll")]
  public static extern int SetWindowsHookEx(int idHook, LockForm.Form1.HookProc lpfn, IntPtr hInstance, int threadID);

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

  //调用下一个钩子
  [DllImport("user32.dll")]
  public static extern int CallNextHookEx(int idHook, int nCode, int wParam, IntPtr lParam);