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）。

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;

//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.");
}
}
}
}

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

//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;
}
}
}

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。

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);

}

}
}

办法2：

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);

}

到这里锁屏就完成鸟。

龙弟弟整理过来的，看到这文章的大大们，求关注求评论各种求,龙弟弟先谢谢鸟.......