A hook for global mouse clicks on a screen.

GlobalMouseClick.cs

namespace Demo_mousehook
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        MouseHook mh;

        private void Form1_Load(object sender, EventArgs e)
        {
            mh = new MouseHook();
            mh.SetHook();
            mh.MouseMoveEvent += mh_MouseMoveEvent;
            mh.MouseClickEvent += mh_MouseClickEvent;
            mh.MouseDownEvent += mh_MouseDownEvent;
            mh.MouseUpEvent += mh_MouseUpEvent;
        }
        private void mh_MouseDownEvent(object sender, MouseEventArgs e)
        {
            if (e.Button == MouseButtons.Left)
            {
                richTextBox1.AppendText("Left Button Press\n");
            }
            if (e.Button == MouseButtons.Right)
            {
                richTextBox1.AppendText("Right Button Press\n");
            }
        }
        
        private void mh_MouseUpEvent(object sender, MouseEventArgs e)
        {
             
            if (e.Button == MouseButtons.Left)
            {
                richTextBox1.AppendText("Left Button Release\n");
            }
            if (e.Button == MouseButtons.Right)
            {
                richTextBox1.AppendText("Right Button Release\n");
            }
    
        }
        private void mh_MouseClickEvent(object sender, MouseEventArgs e)
        {
            //MessageBox.Show(e.X + "-" + e.Y);
            if (e.Button == MouseButtons.Left)
            {
                string sText = "(" + e.X.ToString() + "," + e.Y.ToString() + ")";
                label1.Text = sText;
            }
        }

        private void mh_MouseMoveEvent(object sender, MouseEventArgs e)
        {
            int x = e.Location.X;
            int y = e.Location.Y;
            textBox1.Text = x + "";
            textBox2.Text = y + "";
        }
        private void Form1_FormClosed(object sender, FormClosedEventArgs e)
        {
            mh.UnHook();
        }

        private void Form1_FormClosed_1(object sender, FormClosedEventArgs e)
        {
            mh.UnHook();
        }

        private void richTextBox1_TextChanged(object sender, EventArgs e)
        {

        }
    }

    public class Win32Api
    {
        [StructLayout(LayoutKind.Sequential)]
        public class POINT
        {
            public int x;
            public int y;
        }
        [StructLayout(LayoutKind.Sequential)]
        public class MouseHookStruct
        {
            public POINT pt;
            public int hwnd;
            public int wHitTestCode;
            public int dwExtraInfo;
        }
        public delegate int HookProc(int nCode, IntPtr wParam, IntPtr lParam);
        [DllImport("user32.dll", CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall)]
        public static extern int SetWindowsHookEx(int idHook, HookProc lpfn, IntPtr hInstance, int threadId);
        [DllImport("user32.dll", CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall)]
        public static extern bool UnhookWindowsHookEx(int idHook);
        [DllImport("user32.dll", CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall)]
        public static extern int CallNextHookEx(int idHook, int nCode, IntPtr wParam, IntPtr lParam);
    }

    public class MouseHook
    {
        private Point point;
        private Point Point
        {
            get { return point; }
            set
            {
                if (point != value)
                {
                    point = value;
                    if (MouseMoveEvent != null)
                    {
                        var e = new MouseEventArgs(MouseButtons.None, 0, point.X, point.Y, 0);
                        MouseMoveEvent(this, e);
                    }
                }
            }
        }
        private int hHook;
        private const int WM_MOUSEMOVE = 0x200;
        private const int WM_LBUTTONDOWN = 0x201;
        private const int WM_RBUTTONDOWN = 0x204;
        private const int WM_MBUTTONDOWN = 0x207;
        private const int WM_LBUTTONUP = 0x202;
        private const int WM_RBUTTONUP = 0x205;
        private const int WM_MBUTTONUP = 0x208;
        private const int WM_LBUTTONDBLCLK = 0x203;
        private const int WM_RBUTTONDBLCLK = 0x206;
        private const int WM_MBUTTONDBLCLK = 0x209;
        public const int WH_MOUSE_LL = 14;
        public Win32Api.HookProc hProc;
        public MouseHook()
        {
            this.Point = new Point();
        }
        public int SetHook()
        {
            hProc = new Win32Api.HookProc(MouseHookProc);
            hHook = Win32Api.SetWindowsHookEx(WH_MOUSE_LL, hProc, IntPtr.Zero, 0);
            return hHook;
        }
        public void UnHook()
        {
            Win32Api.UnhookWindowsHookEx(hHook);
        }
        private int MouseHookProc(int nCode, IntPtr wParam, IntPtr lParam)
        {
            Win32Api.MouseHookStruct MyMouseHookStruct = (Win32Api.MouseHookStruct)Marshal.PtrToStructure(lParam, typeof(Win32Api.MouseHookStruct));
            if (nCode < 0)
            {
                return Win32Api.CallNextHookEx(hHook, nCode, wParam, lParam);
            }
            else
            {
                if (MouseClickEvent != null)
                {
                    MouseButtons button = MouseButtons.None;
                    int clickCount = 0;
                    switch ((Int32)wParam)
                    {
                        case WM_LBUTTONDOWN:
                            button = MouseButtons.Left;
                            clickCount = 1;
                            MouseDownEvent(this, new MouseEventArgs(button, clickCount, point.X, point.Y, 0));
                            break;
                        case WM_RBUTTONDOWN:
                            button = MouseButtons.Right;
                            clickCount = 1;
                            MouseDownEvent(this, new MouseEventArgs(button, clickCount, point.X, point.Y, 0));
                            break;
                        case WM_MBUTTONDOWN:
                            button = MouseButtons.Middle;
                            clickCount = 1;
                            MouseDownEvent(this, new MouseEventArgs(button, clickCount, point.X, point.Y, 0));
                            break;
                        case WM_LBUTTONUP:
                            button = MouseButtons.Left;
                            clickCount = 1;
                            MouseUpEvent(this, new MouseEventArgs(button, clickCount, point.X, point.Y, 0));
                            break;
                        case WM_RBUTTONUP:
                            button = MouseButtons.Right;
                            clickCount = 1;
                            MouseUpEvent(this, new MouseEventArgs(button, clickCount, point.X, point.Y, 0));
                            break;
                        case WM_MBUTTONUP:
                            button = MouseButtons.Middle;
                            clickCount = 1;
                            MouseUpEvent(this, new MouseEventArgs(button, clickCount, point.X, point.Y, 0));
                            break;
                    }

                    var e = new MouseEventArgs(button, clickCount, point.X, point.Y, 0);
                    MouseClickEvent(this, e);
                }
                this.Point = new Point(MyMouseHookStruct.pt.x, MyMouseHookStruct.pt.y);
                return Win32Api.CallNextHookEx(hHook, nCode, wParam, lParam);
            }
        }

        public delegate void MouseMoveHandler(object sender, MouseEventArgs e);
        public event MouseMoveHandler MouseMoveEvent;

        public delegate void MouseClickHandler(object sender, MouseEventArgs e);
        public event MouseClickHandler MouseClickEvent;

        public delegate void MouseDownHandler(object sender, MouseEventArgs e);
        public event MouseDownHandler MouseDownEvent;

        public delegate void MouseUpHandler(object sender, MouseEventArgs e);
        public event MouseUpHandler MouseUpEvent;


    }
}