c#操作浏览器dom对象

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

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

        private void button1_Click(object sender, EventArgs e)
        {
            this.webBrowser1.Url =new Uri("http://www.163.com");
        }

        private void webBrowser1_Navigating(object sender, WebBrowserNavigatingEventArgs e)
        {
            //System.Windows.Forms.HtmlDocument document=this.webBrowser1.Document;

            //if (document != null && document.All["userName"] != null &&String.IsNullOrEmpty(document.All["userName"].GetAttribute("value")))
            //{
            //    e.Cancel = true;
            //    System.Windows.Forms.MessageBox.Show(e.Url.ToString());
            //}


        }

        private void button2_Click(object sender, EventArgs e)
        {
            System.Windows.Forms.HtmlDocument document = this.webBrowser1.Document;
            document.All["userName"].SetAttribute("value", "jiasongmao");
            document.All["password"].SetAttribute("value", "1111456433535341111");
            document.All["loginSelect"].SetAttribute("value", "163邮箱");
            document.All["loginSelect"].SetAttribute("value", "163邮箱");
            HtmlElement submitButton = document.Forms["login"];
            MessageBox.Show(submitButton.InnerHtml);
        }
    }
}
http://hi.baidu.com/wangzhe1945/blog/item/0a5fa33e66af9cfc838b134c.html