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using System;
using System.Diagnostics;
using System.Runtime.InteropServices;

namespace HWL.LOCKDESKTOP
{
class Hook
{
//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;
}

//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;
//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);

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

/// 取消钩子事件
public void Hook_Clear()
{
bool retKeyboard = true;
if (hHook != 0)
{
retKeyboard = UnhookWindowsHookEx(hHook);
hHook = 0;
}
}

/// 屏蔽键盘
public static int KeyBoardHookProc(int nCode, int wParam, IntPtr lParam)
{
if (nCode >= 0)
{
KeyBoardHookStruct kbh = (KeyBoardHookStruct)Marshal.PtrToStructure(lParam, typeof(KeyBoardHookStruct));
if ((kbh.vkCode == (int)Keys.LWin) || (kbh.vkCode == (int)Keys.RWin)) //屏蔽左Win和右Win
return 1;
if (kbh.vkCode == (int)Keys.Escape && (int)Control.ModifierKeys == (int)Keys.Control + (int)Keys.Shift) //屏蔽Ctrl+Esc+Shift
return 1;
if (kbh.vkCode == (int)Keys.F4 && (int)Control.ModifierKeys == (int)Keys.Alt) //屏蔽Alt+F4
return 1;
if (kbh.vkCode == (int)Keys.Escape && (int)Control.ModifierKeys == (int)Keys.Alt) //屏蔽Alt+Esc
return 1;
if (kbh.vkCode == (int)Keys.Tab && (int)Control.ModifierKeys == (int)Keys.Alt) //屏蔽Alt+Tab
return 1;
if (kbh.vkCode == (int)Keys.A && (int)Control.ModifierKeys == (int)Keys.Control + (int)Keys.Alt) //屏蔽Control+Alt+A
return 1;
if (kbh.vkCode == (int)Keys.Space && (int)Control.ModifierKeys == (int)Keys.Alt) //屏蔽Alt+Space
return 1;
if (kbh.vkCode == (int)Keys.Shift && (int)Control.ModifierKeys == (int)Keys.Control) //屏蔽Alt+Space
return 1;
if (kbh.vkCode == (int)Keys.L && (int)Control.ModifierKeys == (int)Keys.LWin) //屏蔽左Win+L
return 1;
if (kbh.vkCode == (int)Keys.L && (int)Control.ModifierKeys == (int)Keys.RWin) //屏蔽右Win+L
return 1;
}
return CallNextHookEx(hHook, nCode, wParam, lParam);
}
}
}