wpf 屏蔽热键

using System;
using System.Windows;
using System.Runtime.InteropServices;

namespace WpfApplication1
{
    /// <summary>
    /// Interaction logic for App.xaml
    /// </summary>
    public partial class App : Application
    {
        private struct KBDLLHOOKSTRUCT
        {
            public int vkCode;
            int scanCode;
            public int flags;
            int time;
            int dwExtraInfo;
        }

        private delegate int LowLevelKeyboardProcDelegate(int nCode, int wParam, ref KBDLLHOOKSTRUCT lParam);

        [DllImport("user32.dll")]
        private static extern IntPtr SetWindowsHookEx(int idHook, LowLevelKeyboardProcDelegate lpfn, IntPtr hMod, int dwThreadId);

        [DllImport("user32.dll")]
        private static extern bool UnhookWindowsHookEx(IntPtr hHook);

        [DllImport("user32.dll")]
        private static extern int CallNextHookEx(int hHook, int nCode, int wParam, ref KBDLLHOOKSTRUCT lParam);

        [DllImport("kernel32.dll")]
        private static extern IntPtr GetModuleHandle(IntPtr path);

        private IntPtr hHook;
        LowLevelKeyboardProcDelegate hookProc; // prevent gc
        const int WH_KEYBOARD_LL = 13;

        public App()
        {
            // hook keyboard
            IntPtr hModule = GetModuleHandle(IntPtr.Zero);
            hookProc = new LowLevelKeyboardProcDelegate(LowLevelKeyboardProc);
            hHook = SetWindowsHookEx(WH_KEYBOARD_LL, hookProc, hModule, 0);
            if (hHook == IntPtr.Zero)
            {
                MessageBox.Show("Failed to set hook, error = " + Marshal.GetLastWin32Error());
            }
        }

        protected override void OnExit(ExitEventArgs e)
        {
            UnhookWindowsHookEx(hHook); // release keyboard hook
            base.OnExit(e);
        }

        private static int LowLevelKeyboardProc(int nCode, int wParam, ref KBDLLHOOKSTRUCT lParam)
        {
            if (nCode >= 0)
                switch (wParam)
                {
                    case 256: // WM_KEYDOWN
                    case 257: // WM_KEYUP
                    case 260: // WM_SYSKEYDOWN
                    case 261: // M_SYSKEYUP
                        if (
                            (lParam.vkCode == 0x09 && lParam.flags == 32) || // Alt+Tab
                            (lParam.vkCode == 0x1b && lParam.flags == 32) || // Alt+Esc
                            (lParam.vkCode == 0x73 && lParam.flags == 32) || // Alt+F4
                            (lParam.vkCode == 0x1b && lParam.flags == 0)  || // Ctrl+Esc
                            (lParam.vkCode == 0x5b && lParam.flags == 1)  || // Left Windows Key 
                            (lParam.vkCode == 0x5c && lParam.flags == 1))    // Right Windows Key 
                        {
                            return 1;
                        }
                        break;
                }
            return CallNextHookEx(0, nCode, wParam, ref lParam);
        }
    }
}