方法一:采用 WebClient ,代码如下
using System.Net;
{
   string strurl="网址";
   WebClient aWebClient = new WebClient();
   aWebClient.Encoding = System.Text.Encoding.UTF8;
   string htmlcode = aWebClient.DownloadString(strurl);
   txtbox.Text=htmlcode;//txtbox为一个文本框
}
方法二:采用 HttpWebRequest HttpWebResponse ,代码如下
using System.Net;
{
 string strurl = "http://www.weather.com.cn/weather/101310101.shtml?from=cn";
 HttpWebRequest myReq = (HttpWebRequest)WebRequest.Create(strurl);
    myReq.Accept = "Accept-Languat:zh-cn";
    myReq.AllowAutoRedirect = true;
    myReq.MaximumAutomaticRedirections = 1;
    myReq.Referer = "weather";
    HttpWebResponse myResponse = (HttpWebResponse)myReq.GetResponse();
    Stream myStream = myResponse.GetResponseStream();
    StreamReader myReader = new StreamReader(myStream, System.Text.Encoding.UTF8);
    txtbox.Text = myReader.ReadToEnd();//txtbox为一个文本框

}