C# 怎么通过坐标实现模拟点击WebBrowser里面的内容？

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
}
}
}

先获取到HtmlElement对象，然后调用这个对象的InvokeMember("click")方法。