C# .NET锁屏程序（顺带屏蔽任务管理器）

C# .NET锁屏程序（顺带屏蔽任务管理器）

第一步：将窗体的FormBorderStyle设置为none，WindowState设为Maximized

占据整个屏幕。

第二步：使用钩子监控全局键盘事件。即屏蔽掉大部分系统热键。但是屏蔽ctrl+alt+del 任务管理器则较复杂，这个特例后面讨论。

使用全局钩子应该注意的地方：将代码放到一个独立的类库里面（只有dll才能被注射到其他进程中）。

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using System;

using System.Collections.Generic;

using System.Text;

using System.Runtime.InteropServices;

using System.IO;

using System.Reflection;

namespace KeyboardHookDLL

{

    public class KeyboardHook

    {

        public delegate int KeyboardProc(int nCode, IntPtr wParam, IntPtr lParam);

        static int hKeyboardHook = 0;

        KeyboardProc KeyboardHookProcedure;

        /// <summary>

        /// 钩子函数,需要引用空间(using System.Reflection;)

        /// 线程钩子监听键盘消息设为2,全局钩子监听键盘消息设为13

        /// 线程钩子监听鼠标消息设为7,全局钩子监听鼠标消息设为14

        /// </summary>

        public const int WH_KEYBOARD = 13;

        public const int WH_MOUSE_LL = 14;

        public struct KeyboardMSG

        {

            public int vkCode;

            public int scanCode;

            public int flags;

            public int time;

            public int dwExtraInfo;

        }

        //private FileStream MyFs;

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//各种键位的ASC码

        private const byte LLKHF_ALTDOWN = 0x20;

        private const byte VK_CAPITAL = 0x14;

        private const byte VK_ESCAPE = 0x1B;

        private const byte VK_F4 = 0x73;

        private const byte VK_LCONTROL = 0xA2;

        private const byte VK_NUMLOCK = 0x90;

        private const byte VK_RCONTROL = 0xA3;

        private const byte VK_SHIFT = 0x10;

        private const byte VK_TAB = 0x09;

        //public const int WH_KEYBOARD = 13;

        private const int WH_KEYBOARD_LL = 13;

        private const int WH_MOUSE = 7;

        //private const int WH_MOUSE_LL = 14;

        private const int WM_KEYDOWN = 0x100;

        private const int WM_KEYUP = 0x101;

        private const int WM_LBUTTONDBLCLK = 0x203;

        private const int WM_LBUTTONDOWN = 0x201;

        private const int WM_LBUTTONUP = 0x202;

        private const int WM_MBUTTONDBLCLK = 0x209;

        private const int WM_MBUTTONDOWN = 0x207;

        private const int WM_MBUTTONUP = 0x208;

        private const int WM_MOUSEMOVE = 0x200;

        private const int WM_MOUSEWHEEL = 0x020A;

        private const int WM_RBUTTONDBLCLK = 0x206;

        private const int WM_RBUTTONDOWN = 0x204;

        private const int WM_RBUTTONUP = 0x205;

        private const int WM_SYSKEYDOWN = 0x104;

        private const int WM_SYSKEYUP = 0x105;

        //private static int hKeyboardHook = 0;

        /// <summary>

        /// vs2008中的声明方法，在vs2010中略有不同

        /// </summary>

        /// <returns></returns>

        [DllImport("kernel32")]

        public static extern int GetCurrentThreadId();

        [DllImport("user32.dll", CharSet = CharSet.Auto, CallingConvention =

CallingConvention.StdCall)]

        public static extern int SetWindowsHookEx(int idHook, KeyboardProc lpfn, IntPtr

hInstance, int threadId);

        [DllImport("user32.dll", CharSet = CharSet.Auto, CallingConvention =

CallingConvention.StdCall)]

        public static extern bool UnhookWindowsHookEx(int idHook);

        [DllImport("user32.dll", CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall)]

        public static extern int CallNextHookEx(int idHook, int nCode, IntPtr wParam, IntPtr lParam);

        [DllImport("user32.dll", CharSet = CharSet.Auto, CallingConvention = CallingConvention.Winapi)]

        public static extern short GetKeyState(int keycode);

//在这里你可以自己定义要拦截的键。

        private int KeyboardHookProc(int nCode, IntPtr wParam, IntPtr lParam)

        {

            KeyboardMSG m = (KeyboardMSG)Marshal.PtrToStructure(lParam, typeof(KeyboardMSG));

             if (

            ((int)m.vkCode == 91) || ((int)m.vkCode == 92) ||

            //两个组合键

            ((m.vkCode == VK_TAB) && ((m.flags & LLKHF_ALTDOWN) != 0)) ||

            ((m.vkCode == VK_ESCAPE) && ((m.flags & LLKHF_ALTDOWN) != 0)) ||

            ((m.vkCode == VK_F4) && ((m.flags & LLKHF_ALTDOWN) != 0)) ||

            //用于三个组合键

            (m.vkCode == VK_ESCAPE) && ((GetKeyState(VK_LCONTROL) & 0x8000) != 0) ||

            ((int)m.vkCode >= 65 && (int)m.vkCode <= 90 && ((GetKeyState(0x12) & 0x8000) != 0) ) ||

            ((int)m.vkCode >= 65 && (int)m.vkCode <= 90&& ((GetKeyState(0x11) & 0x8000) != 0)) ||

            (m.vkCode == VK_ESCAPE) && ((GetKeyState(VK_RCONTROL) & 0x8000) != 0)

            )

            {

                return 1;

            }

            return CallNextHookEx(hKeyboardHook, nCode, wParam, lParam);

        }

   // 安装钩子

        public void KeyMaskStart()

        {

            if (hKeyboardHook == 0)

            {

                // 创建HookProc实例

                KeyboardHookProcedure = new KeyboardProc(KeyboardHookProc);

                // 设置线程钩子

                hKeyboardHook = SetWindowsHookEx(WH_KEYBOARD, KeyboardHookProcedure,

                    Marshal.GetHINSTANCE(Assembly.GetExecutingAssembly().GetModules()[0]), 0);

                // 如果设置钩子失败

                if (hKeyboardHook == 0)

                {

                    KeyMaskStop();

                    throw new Exception("SetWindowsHookEx failed.");

                }

                ////用二进制流的方法打开任务管理器。而且不关闭流.这样任务管理器就打开不了

                //MyFs = new FileStream(Environment.ExpandEnvironmentVariables("%windir%\\system32\\taskmgr.exe"),

                //FileMode.Open);

                //byte[] MyByte = new byte[(int)MyFs.Length];

                //MyFs.Write(MyByte, 0, (int)MyFs.Length);

            }

        }

        // 卸载钩子

        public void KeyMaskStop()

        {

            bool retKeyboard = true;

            if (hKeyboardHook != 0)

            {

                retKeyboard = UnhookWindowsHookEx(hKeyboardHook);

                hKeyboardHook = 0;

            }

            if (!(retKeyboard))

            {

                throw new Exception("UnhookWindowsHookEx  failed.");

            }

        }

    }

}

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第三步：这个时候你会发现，程序能屏蔽大部分的热键了，唯独ctrl+alt+del，你无论怎么去拦截，只要你按下这三个键，任务管理器活灵活现的出来了。

原因：这个组合键是系统级别滴（唯一的，ctrl+shift+esc不是）。普通的软件拦截是木有用的。得驱动级啥的才行吧。

既然如此，就只能转换思路了。既然不能治本，治标也行，只要能达到目的。

 

思路有两个：1是让任务管理器一旦运行就被结束，让用户不能操作。2是让任务管理器以另外的方式先运行并隐藏起来，用户就不能运行了。

 

思路1的代码：使用timer控件

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//引用这个空间using System.Diagnostics;

        private void timer1_Tick(object sender, EventArgs e)

        {

            Process[] p = Process.GetProcesses();

            foreach (Process p1 in p)

            {

                try

                {

                    if (p1.ProcessName.ToLower().Trim() == "taskmgr")//这里判断是任务管理器   

                    {

                        p1.Kill();

                        return;

                    }

                }

                catch

                {

                    return;

                }

            }

        }

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思路2有两个比较好的办法

还有个不咋滴的办法，就是以文件流的方式打开taskmgr.exe（代码在上面的KeyboardHookDLL中能找到），在xp下还行，到win7下面就会有提示了。

办法1：以隐藏的方式运行。

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using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.Text;

using System.Windows.Forms;

using Microsoft.Win32;

using System.Diagnostics;

using System.Runtime.InteropServices;

namespace KidWorld

{

    public partial class Form1 : Form

    {

        [DllImport("user32.dll")]

        public static extern int FindWindow(string lpClassName, string lpWindowName);

        [DllImport("User32.dll")]

        public static extern Int32 SendMessage(

        int hWnd, // handle to destination window

        int Msg, // message

        int wParam, // first message parameter

        int lParam); // second message parameter

        public Form1()

        {

            InitializeComponent();

        }

        private void Form1_Load(object sender, EventArgs e)

        {

            Process p = new Process();

            p.StartInfo.WorkingDirectory = Environment.GetFolderPath(Environment.SpecialFolder.System);

            p.StartInfo.FileName = "taskmgr.exe";

            p.StartInfo.CreateNoWindow = true;

            p.StartInfo.WindowStyle = ProcessWindowStyle.Hidden;

            p.Start();

        }

        private void Form1_FormClosing(object sender, FormClosingEventArgs e)

        {

            const int WM_CLOSE = 0x0010;

            int taskManager = FindWindow("#32770", "Windows Task Manager");

            SendMessage(taskManager, WM_CLOSE, 0, 0);

        }

    }

}

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办法2：

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private void Form1_Load(object sender, EventArgs e)

        {

            //this.Text =Environment.GetFolderPath( Environment.SpecialFolder.System).ToString();

            blockTaskMgr();

        }

        void blockTaskMgr() {

            //阻塞其他程序读取

            Stream oStream = File.Open(@"C:\WINDOWS\system32\taskmgr.exe", FileMode.OpenOrCreate, FileAccess.Write);

        }

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