最近做的一個winform類型的項目中需要屏蔽系統熱鍵,在網上搜索了一下,基本上都是調用api來進行hook操作,下面的代碼就可以完成功能
using System;
using System.IO;
using System.Reflection;
using System.Runtime.InteropServices;
using System.Windows.Forms;

namespace WAT.PMS
{

/// <summary>
/// Description: Hook Helper類,可以屏蔽一些熱鍵並屏蔽任務管理器
/// Author: ZhangRongHua
/// Create DateTime: 2009-6-19 20:21
/// UpdateHistory:
/// </summary>
public class HookHelper
{
#region Delegates

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

#endregion

#region 變量聲明

private HookProc KeyboardHookProcedure;
private FileStream MyFs; // 用流來屏蔽ctrl alt delete

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;

#endregion

#region 函數轉換

[DllImport("user32.dll", CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall)]
public static extern int SetWindowsHookEx(int idHook, HookProc lpfn, IntPtr hInstance, int threadId);

// 卸載鈎子

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

// 繼續下一個鈎子

[DllImport("user32.dll", CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall)]
public static extern int CallNextHookEx(int idHook, int nCode, Int32 wParam, IntPtr lParam);

// 取得當前線程編號

[DllImport("kernel32.dll")]
private static extern int GetCurrentThreadId();

[DllImport("user32.dll", CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall)]
private static extern short GetKeyState(int vKey);

#endregion

#region 方法

/// <summary>
/// 鈎子回調函數,在這里屏蔽熱鍵。
/// <remark>
/// Author:ZhangRongHua
/// Create DateTime: 2009-6-19 20:19
/// Update History:
/// </remark>
/// </summary>
/// <param name="nCode">The n code.</param>
/// <param name="wParam">The w param.</param>
/// <param name="lParam">The l param.</param>
/// <returns></returns>
private int KeyboardHookProc(int nCode, Int32 wParam, IntPtr lParam)
{
KeyMSG m = (KeyMSG) Marshal.PtrToStructure(lParam, typeof (KeyMSG));

if (((Keys) m.vkCode == Keys.LWin) || ((Keys) m.vkCode == Keys.RWin) ||
((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)) ||
(m.vkCode == VK_ESCAPE) && ((GetKeyState(VK_LCONTROL) & 0x8000) != 0) ||
(m.vkCode == VK_ESCAPE) && ((GetKeyState(VK_RCONTROL) & 0x8000) != 0)
)
{
return 1;
}

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

/// <summary>
/// 啟動Hook,並用流屏蔽任務管理器
/// <remark>
/// Author:ZhangRongHua
/// Create DateTime: 2009-6-19 20:20
/// Update History:
/// </remark>
/// </summary>
public void HookStart()
{
if (hKeyboardHook == 0)
{
// 創建HookProc實例

KeyboardHookProcedure = new HookProc(KeyboardHookProc);

hKeyboardHook = SetWindowsHookEx(WH_KEYBOARD,
KeyboardHookProcedure,
Marshal.GetHINSTANCE(Assembly.GetExecutingAssembly().GetModules()[0]),
0);

// 如果設置鈎子失敗

if (hKeyboardHook == 0)
{
HookStop();

//throw new Exception("SetWindowsHookEx failedeeeeeeee.");
}

//用二進制流的方法打開任務管理器。而且不關閉流.這樣任務管理器就打開不了
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);
}
}



/// <summary>
/// 卸載hook,並關閉流,取消屏蔽任務管理器。
/// <remark>
/// Author:ZhangRongHua
/// Create DateTime: 2009-6-19 20:21
/// Update History:
/// </remark>
/// </summary>
public void HookStop()
{
bool retKeyboard = true;

if (hKeyboardHook != 0)
{
retKeyboard = UnhookWindowsHookEx(hKeyboardHook);

hKeyboardHook = 0;
}

if (null != MyFs)
{
MyFs.Close();
}

if (!(retKeyboard))
{
throw new Exception("UnhookWindowsHookEx failedsssss.");
}
}

#endregion

#region Nested type: KeyMSG

public struct KeyMSG
{
public int dwExtraInfo;
public int flags;
public int scanCode;

public int time;
public int vkCode;
}

#endregion
}
}
PS:也可以通過將[HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\System] 下的DisableTaskmgr項的值設為"1”來屏蔽任務管理器。
也可以參考:如何使用注冊表禁用任務管理器 http://jingyan.baidu.com/article/1e5468f91d8813484861b769.html 百度經驗
參考:http://www.cnblogs.com/zhangronghua/archive/2009/06/19/1507031.html