c# 在WebBrowser中用SendMessage模拟鼠标点击

代码如下:
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 BrowserMouseClick
{
public partial class Form1 : Form
{
     [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = false)]
     static extern IntPtr SendMessage(IntPtr hWnd, uint Msg, IntPtr wParam, IntPtr lParam);

     [DllImport("user32.dll", SetLastError = true)]
     static extern IntPtr GetWindow(IntPtr hWnd, uint uCmd);

     [DllImport("user32.dll", CharSet = CharSet.Auto)]
     static extern int GetClassName(IntPtr hWnd, StringBuilder lpClassName, int nMaxCount);

     public Form1()
     {
         InitializeComponent();
     }

     private void Form1_Load(object sender, EventArgs e)
     {
         webBrowser1.Navigate("http://www.devpub.com");
     }

     private void btnMouseClick_Click(object sender, EventArgs e)
     {
         int x = 100; // X coordinate of the click
         int y = 80; // Y coordinate of the click
         IntPtr handle = webBrowser1.Handle;
         StringBuilder className = new StringBuilder(100);
         while (className.ToString() != "Internet Explorer_Server") // The class control for the browser
         {
             handle = GetWindow(handle, 5); // Get a handle to the child window
             GetClassName(handle, className, className.Capacity);
         }

         IntPtr lParam = (IntPtr)((y << 16) | x); // The coordinates
         IntPtr wParam = IntPtr.Zero; // Additional parameters for the click (e.g. Ctrl)
         const uint downCode = 0x201; // Left click down code
         const uint upCode = 0x202; // Left click up code
         SendMessage(handle, downCode, wParam, lParam); // Mouse button down
         SendMessage(handle, upCode, wParam, lParam); // Mouse button up
     }
}
}

想在WebBrowser控件里面模拟鼠标点击，在百度上找了半天，怎么也找不到，还是google强大，在一个国外网站上找到的，代码比较清楚了，不做说明。