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

namespace WindowsApplication3
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        public delegate int HookProc(int nCode, IntPtr wParam, IntPtr lParam);
        //定义钩子句柄
        static int hHook = 0;
        //定义钩子类型
        public const int WH_MOUSE = 7;
        //定义钩子处理函数
        HookProc MouseHookProcedure;
        [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;
        }

        //导入windows Api函数声明,这里要用到的函数有
        //SetWindowsHookEx,UnhookWindowsHookEx,CallNextHookEx
        [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);

        private void button1_Click(object sender, EventArgs e)
        {
            if (hHook == 0)
            {
                MouseHookProcedure = new HookProc(Form1.MouseHookProc);
                //这里挂节钩子
                hHook = SetWindowsHookEx(WH_MOUSE,
                MouseHookProcedure,
                (IntPtr)0,
                AppDomain.GetCurrentThreadId());

                if (hHook == 0)
                {
                    MessageBox.Show("SetWindowsHookEx Failed");
                    return;
                }
                button1.Text = "UnHook Windows Hook";
            }
            else
            {
                bool ret = UnhookWindowsHookEx(hHook);
                if (ret == false)
                {
                    MessageBox.Show("UnhookWindowsHookEx Failed");
                    return;
                }
                hHook = 0;
                button1.Text = "Set Windows Hook";
                this.Text = "Mouse Hook";
            }

        }

        public static int MouseHookProc(int nCode, IntPtr wParam, IntPtr lParam)
        {
            MouseHookStruct MyMouseHookStruct = (MouseHookStruct)Marshal.PtrToStructure(lParam, typeof(MouseHookStruct));

            if (nCode < 0)
            {
                return CallNextHookEx(hHook, nCode, wParam, lParam);
            }
            else
            {
                String strCaption = "x = " +
                MyMouseHookStruct.pt.x.ToString("d") +
                "  y = " +
                MyMouseHookStruct.pt.y.ToString("d");
                Form tempForm = Form.ActiveForm;

                tempForm.Text = strCaption;
                return CallNextHookEx(hHook, nCode, wParam, lParam);
            }
        }

    }
}