InterceptKeys.cs

using System;
using System.Diagnostics;
using System.Windows.Forms;
using System.Runtime.InteropServices;

public static class InterceptKeys
{
    private const int WH_KEYBOARD_LL = 13;
    public const int WM_KEYDOWN = 0x100;
    public const int WM_KEYUP = 0x101;
    public const int WM_CHAR = 0x105;
    public const int WM_SYSKEYDOWN = 0x104;
    public const int WM_SYSKEYUP = 0x105;

    private static LowLevelKeyboardProc _proc = HookCallback;
    private static IntPtr _hookID = IntPtr.Zero;
    public static event HookDelegate Hook;

    public delegate void HookDelegate(int nCode, int vkCode, int wParam);

    public static void InitializeComponent()
    {
        _hookID = SetHook(_proc);
        //Application.Run();
        //UnhookComponent();
    }

    public static void UnhookComponent()
    { 
        UnhookWindowsHookEx(_hookID);
    }

    private static IntPtr SetHook(LowLevelKeyboardProc proc)
    {
        using (Process curProcess = Process.GetCurrentProcess())
        using (ProcessModule curModule = curProcess.MainModule)
        {
            return SetWindowsHookEx(WH_KEYBOARD_LL, proc,
                GetModuleHandle(curModule.ModuleName), 0);
        }
    }

    private delegate IntPtr LowLevelKeyboardProc(
        int nCode, IntPtr wParam, IntPtr lParam);

    private static IntPtr HookCallback(
        int nCode, IntPtr wParam, IntPtr lParam)
    {
        if (Hook != null)
        {
            int vkCode = Marshal.ReadInt32(lParam);
            int wmCode = wParam.ToInt32();
            Hook(nCode, vkCode, wmCode);
        }
        //if (nCode >= 0 && wParam == (IntPtr)WM_KEYDOWN)
        //{
        //    int vkCode = Marshal.ReadInt32(lParam);
        //    Console.WriteLine((Keys)vkCode);
        //}
        return CallNextHookEx(_hookID, nCode, wParam, lParam);
    }

    [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
    private static extern IntPtr SetWindowsHookEx(int idHook,
        LowLevelKeyboardProc lpfn, IntPtr hMod, uint dwThreadId);

    [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
    [return: MarshalAs(UnmanagedType.Bool)]
    public static extern bool UnhookWindowsHookEx(IntPtr hhk);

    [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
    private static extern IntPtr CallNextHookEx(IntPtr hhk, int nCode,
        IntPtr wParam, IntPtr lParam);

    [DllImport("kernel32.dll", CharSet = CharSet.Auto, SetLastError = true)]
    private static extern IntPtr GetModuleHandle(string lpModuleName);
}