Question

C#中怎么屏蔽组合键？

想做个程序貌似像一个屏幕锁，请各位帮帮忙怎么实现？我的想法是把系统的组合键屏蔽了就可以了（Alt+F4，Ctrl+Alt+Delete,Alt+Tab等等）！
有别的想法的也可以说说啊！
Ctrl+Alt+Delete 还是不行！

Answer 1

貌似只能通过hook,

参考
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Runtime.InteropServices;
using System.Reflection;
using System.Diagnostics;
using Microsoft.Win32;

namespace WindowsApplication1
{
public partial class Form2 : Form
{
//委托
public delegate int HookProc(int nCode, int wParam, IntPtr lParam);
static int hHook = 0;
public const int WH_KEYBOARD_LL = 13;

//LowLevel键盘截获，如果是WH_KEYBOARD＝2，并不能对系统键盘截取，Acrobat Reader会在你截取之前获得键盘。
HookProc KeyBoardHookProcedure;

//键盘Hook结构函数
[StructLayout(LayoutKind.Sequential)]
public class KeyBoardHookStruct
{
public int vkCode;
public int scanCode;
public int flags;
public int time;
public int dwExtraInfo;
}
#region DllImport
//设置钩子
[DllImport("user32.dll")]
public static extern int SetWindowsHookEx(int idHook, HookProc lpfn, IntPtr hInstance, int threadId);
[DllImport("user32.dll", CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall)]
//抽掉钩子
public static extern bool UnhookWindowsHookEx(int idHook);
[DllImport("user32.dll")]
//调用下一个钩子
public static extern int CallNextHookEx(int idHook, int nCode, int wParam, IntPtr lParam);

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

[DllImport("kernel32.dll")]
public static extern IntPtr GetModuleHandle(string name);

public void Hook_Start()
{
// 安装键盘钩子
if (hHook == 0)
{
KeyBoardHookProcedure = new HookProc(KeyBoardHookProc);

//hHook = SetWindowsHookEx(2,
// KeyBoardHookProcedure,
// GetModuleHandle(Process.GetCurrentProcess().MainModule.ModuleName), GetCurrentThreadId());

hHook = SetWindowsHookEx(WH_KEYBOARD_LL,
KeyBoardHookProcedure,
GetModuleHandle(Process.GetCurrentProcess().MainModule.ModuleName), 0);

//如果设置钩子失败.
if (hHook == 0)
{
Hook_Clear();
//throw new Exception("设置Hook失败!");
}
}
}

//取消钩子事件
public void Hook_Clear()
{
bool retKeyboard = true;
if (hHook != 0)
{
retKeyboard = UnhookWindowsHookEx(hHook);
hHook = 0;
}
//如果去掉钩子失败.
if (!retKeyboard) throw new Exception("UnhookWindowsHookEx failed.");
}

//这里可以添加自己想要的信息处理
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win(开始菜单键)
{
return 1;
}
if (kbh.vkCode == 92)// 截获右win
{
return 1;
}
if (kbh.vkCode == (int)Keys.Escape && (int)Control.ModifierKeys == (int)Keys.Control) //截获Ctrl+Esc
{
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.Escape && (int)Control.ModifierKeys == (int)Keys.Control + (int)Keys.Shift) //截获Ctrl+Shift+Esc
{
return 1;
}
if (kbh.vkCode == (int)Keys.Space && (int)Control.ModifierKeys == (int)Keys.Alt) //截获alt+空格
{
return 1;
}
if (kbh.vkCode == 241) //截获F1
{
return 1;
}
if ((int)Control.ModifierKeys == (int)Keys.Control + (int)Keys.Alt + (int)Keys.Delete) //截获Ctrl+Alt+Delete
{
return 1;
}
//if ((int)Control.ModifierKeys == (int)Keys.Control + (int)Keys.Shift) //截获Ctrl+Shift
//{
// return 1;
//}

//if (kbh.vkCode == (int)Keys.Space && (int)Control.ModifierKeys == (int)Keys.Control + (int)Keys.Alt) //截获Ctrl+Alt+空格
//{
// return 1;
//}
}
return CallNextHookEx(hHook, nCode, wParam, lParam);
}

#endregion

public Form2()
{
InitializeComponent();
}

private void Form2_Load(object sender, EventArgs e)
{
Hook_Start();

//通过修改注册表来屏蔽任务管理器
//try
//{
// RegistryKey r = Registry.CurrentUser.OpenSubKey("Software\\Microsoft\\Windows\\CurrentVersion\\Policies\\System", true);
// r.SetValue("DisableTaskMgr", "1"); //屏蔽任务管理器
//}
//catch
//{
// RegistryKey r = Registry.CurrentUser.CreateSubKey("Software\\Microsoft\\Windows\\CurrentVersion\\Policies\\System");
// r.SetValue("DisableTaskMgr", "0");
//}
}

private void Form2_FormClosing(object sender, FormClosingEventArgs e)
{
Hook_Clear();
}

private void Form2_MouseMove(object sender, MouseEventArgs e)
{
System.Windows.Forms.Cursor.Clip = new Rectangle(this.Location, this.Size); //控制鼠标在窗口范围内
}
}
}

Answer 2

private void Register_KeyDown(object sender, KeyEventArgs e)
{
if (e.Modifiers == Keys.Alt && e.KeyCode == Keys.F4)
{
e.Handled = true;
}
}

这样就可以屏蔽了。