.net c# 如何獲指定地址的網頁內容標籤

//捉取頁面    protected void Button1_Click(object sender, EventArgs e)    {        WebRequest webRequest = WebRequest.Create(this.txtSearch.Text.Trim());        WebResponse webResponse = webRequest.GetResponse();        Stream stream = webResponse.GetResponseStream();        //StreamReader sr = new StreamReader(stream);        StreamReader sr = new StreamReader(stream, Encoding.Default);        StringBuilder sb = new StringBuilder();        string str=string.Empty;        while ((str = sr.ReadLine()) != null)        {            sb.Append(str).Append("<br/>");        }        this.div.Value = sb.ToString();        this.div2.InnerHtml = sb.ToString();    }