C# Global Keys

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


namespace YetAnotherColorPicker
{
    public partial class Form1 : Form
    {


        private const int WH_KEYBOARD_LL = 13, WM_KEYDOWN = 0x0100;
        private static LowLevelKeyboardProc _proc = HookCallback;
        private static IntPtr _hookID = IntPtr.Zero;


        int x, y;


        Color color;
        Thread t;
        public static Thread timer;


        private bool pickerStartet = false;




        public Form1()
        {
            InitializeComponent();
            instance = this;
            _hookID = SetHook(_proc);
        }


        public void onKeyDown(int keyCode)
        {
            //Debug
            MessageBox.Show(keyCode);
        }


        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 static Form1 instance;
        public static Form1 Instance
        {
            get { return instance; }
        }
        private delegate IntPtr LowLevelKeyboardProc(int nCode, IntPtr wParam, IntPtr lParam);




        private static IntPtr HookCallback(int nCode, IntPtr wParam, IntPtr lParam)
        {


            if (nCode >= 0 && wParam == (IntPtr)WM_KEYDOWN)
            {
                Instance.onKeyDown(Marshal.ReadInt32(lParam));
            }
            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)]


        private 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);

        [DllImport("gdi32.dll", CharSet = CharSet.Auto, SetLastError = true, ExactSpelling = true)]

        public static extern int BitBlt(IntPtr hDC, int x, int y, int nWidth, int nHeight, IntPtr hSrcDC, int xSrc, int ySrc, int dwRop);

        private void Form1_Load(object sender, EventArgs e)
        {
            this.ActiveControl = pickColorPanel;
            //comboBox1.SelectedIndex = 0;


            //this.t.Start();



        }


        private void panel1_Paint(object sender, PaintEventArgs e)
        {


        }
        private void AppendTextLabel()
        {
            if(InvokeRequired)
            {
                this.Invoke(new Action(AppendTextLabel));
                return;
            }
            coordsLabel.Text = "X: " + x.ToString() + " Y: " + y.ToString(); ;
        }


        private void Form1_FormClosed(object sender, FormClosedEventArgs e)
        {
            if (this.pickerStartet == true)
            {
                this.t.Abort();


            }
        }


        private void schließenToolStripMenuItem_Click(object sender, EventArgs e)
        {
            Application.Exit();
        }


        private void neustartenToolStripMenuItem_Click(object sender, EventArgs e)
        {
            Application.Restart();
        }


        private void button2_Click(object sender, EventArgs e)
        {
            if (this.pickerStartet == true)
            {
                this.t.Abort();
                this.pickerStartet = false;
            }
            else
            {
                this.t = new Thread(update);
                this.t.Start();
                this.pickerStartet = true;
            }  
        }


        private void update()
        {
            Bitmap screenCopy = new Bitmap(1, 1);
            using (Graphics gdest = Graphics.FromImage(screenCopy))
            {
                while (true)
                {
                    x = Cursor.Position.X;
                    y = Cursor.Position.Y;
                    using (Graphics gsrc = Graphics.FromHwnd(IntPtr.Zero))
                    {
                        IntPtr hSrcDC = gsrc.GetHdc();
                        IntPtr hDC = gdest.GetHdc();
                        int retval = BitBlt(hDC, 0, 0, 1, 1, hSrcDC, x, y, (int)CopyPixelOperation.SourceCopy);
                        gdest.ReleaseHdc();
                        gsrc.ReleaseHdc();
                    }
                    color = Color.FromArgb(screenCopy.GetPixel(0, 0).ToArgb());
                    pickColorPanel.BackColor = color;
                    AppendTextLabel();
                    Thread.Sleep(50);
                    //MessageBox.Show(c.ToString());


                    
                }
            }




        }


    }
}