ASP.NET抓取网页数据

//根据Url地址得到网页的html源码
private string GetWebContent(string Url)
{
string strResult = "";
try
{
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(Url);
//声明一个HttpWebRequest请求
request.Timeout = 30000;
//设置连接超时时间
request.Headers.Set("Pragma", "no-cache");
HttpWebResponse response = (HttpWebResponse)request.GetResponse();
Stream streamReceive = response.GetResponseStream();
Encoding encoding = Encoding.GetEncoding("utf-8");
StreamReader streamReader = new StreamReader(streamReceive, encoding);
strResult = streamReader.ReadToEnd();
}
catch
{
MessageBox.Show("出错");
}
return strResult;
}

    private void button1_Click(object sender, EventArgs e)
    {
        //要抓取的URL地址 
        string Url = "http://kxt.com/data/20.html";    //☆☆☆☆☆☆☆☆☆☆ 
        //得到指定Url的源码 
        string strWebContent = GetWebContent(Url);
        richTextBox1.Text = strWebContent;
        //取出和数据有关的那段源码 
        int iBodyStart = strWebContent.IndexOf("", iTableStart);
        string strWeb = strWebContent.Substring(iTableStart, iTableEnd - iTableStart + 5);
        //生成HtmlDocument 
        WebBrowser webb = new WebBrowser();
        webb.Navigate("about:blank");
        HtmlDocument htmldoc = webb.Document.OpenNew(true);
        htmldoc.Write(strWeb);
        HtmlElementCollection htmlTR = htmldoc.GetElementsByTagName("li");
        int i = 0;
        foreach (HtmlElement tr in htmlTR)
        {
            i++;
            if (i == 1 )
            {
                continue;
            }
            if (i ==  htmlTR.Count - 2)
            {
                break;
            }
            HtmlElementCollection spans = tr.GetElementsByTagName("span");

            string dateTime = spans[0].InnerText;

            string netWeightOunce = spans[1].InnerText;
            string netWeightTon = spans[2].InnerText;
            string totalValue = spans[3].InnerText;
            string regulation = spans[4].InnerText;
            //string affectOil = spans[5].InnerText;

            //Id, UpdateTime, NetWeightOunce, NetWeightTon, TotalValue, Regulation, FinanceTime
            SqlServer ado=new SqlServer();
            ado.AddField("UpdateTime",DateTime.Now);
            ado.AddField("NetWeightOunce", netWeightOunce);
            ado.AddField("NetWeightTon", netWeightTon);
            ado.AddField("TotalValue", totalValue);
           // ado.AddField("EffectOil", affectOil);
            ado.AddField("Regulation", regulation);
            ado.AddField("FinanceTime", Convert.ToDateTime(dateTime).ToString("yyyy-MM-dd"));//☆☆☆☆☆☆☆☆☆☆

            ado.Insert("Silver");//☆☆☆☆☆☆☆☆☆☆

        }

        MessageBox.Show("OK");

    } 

            例子：

using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Net;
using System.IO;
using System.Text;

public partial class _Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
//要抓取的URL地址
string StrUrl = "http://www.cjh.com.cn/sqindex.html";
//得到指定Url的源码
string StrWebContent = GetWebContent(StrUrl);

    //取出和数据有关的那段源码
    int IndexBodyStart = StrWebContent.IndexOf("

}