using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Runtime.InteropServices;

namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        bool reg = false;

        [DllImport("user32.dll")]
        static extern IntPtr SetWindowsHookEx(HookType code, HookProc func, IntPtr hInstance, int threadID);

        [DllImport("user32.dll")]
        static extern int CallNextHookEx(IntPtr hhk, int nCode, IntPtr wParam, IntPtr lParam);

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

        public Form1()
        {
            InitializeComponent();
        }

        private HookProc myCallbackDelegate = null;

        private delegate int HookProc(int code, IntPtr wParam, IntPtr lParam);

        public enum HookType : int
        {
            WH_JOURNALRECORD = 0,
            WH_JOURNALPLAYBACK = 1,
            WH_KEYBOARD = 2,
            WH_GETMESSAGE = 3,
            WH_CALLWNDPROC = 4,
            WH_CBT = 5,
            WH_SYSMSGFILTER = 6,
            WH_MOUSE = 7,
            WH_HARDWARE = 8,
            WH_DEBUG = 9,
            WH_SHELL = 10,
            WH_FOREGROUNDIDLE = 11,
            WH_CALLWNDPROCRET = 12,
            WH_KEYBOARD_LL = 13,
            WH_MOUSE_LL = 14
        }

        private int MyCallbackFunction(int code, IntPtr wParam, IntPtr lParam)
        {
            if (code < 0)
            {
                //you need to call CallNextHookEx without further processing
                //and return the value returned by CallNextHookEx
                return CallNextHookEx(IntPtr.Zero, code, wParam, lParam);
            }
            // we can convert the 2nd parameter (the key code) to a System.Windows.Forms.Keys enum constant
            //Keys keyPressed = (Keys)wParam.ToInt32();
            //Console.WriteLine(keyPressed);
            if (!reg && wParam != IntPtr.Zero)
            {
                this.Text = wParam.ToString()
                    + " " + lParam.ToString();
                reg = true;
            }
            //return the value returned by CallNextHookEx
            return CallNextHookEx(IntPtr.Zero, code, wParam, lParam);
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            // initialize our delegate
            this.myCallbackDelegate = new HookProc(this.MyCallbackFunction);

            // setup a keyboard hook
            SetWindowsHookEx(HookType.WH_CALLWNDPROC, this.myCallbackDelegate, IntPtr.Zero, (int)GetCurrentThreadId());//AppDomain.GetCurrentThreadId());

            timer1.Start();
        }

        private void timer1_Tick(object sender, EventArgs e)
        {
            reg = false; // Otherwise the RAM jumps to 100%
        }
    }
}