asp.net抓取页面内容+下载文件

#region 抓取页面的内容
public string GetHTML(string url)
{
ASCIIEncoding encoding = new ASCIIEncoding();
byte[] postdata = encoding.GetBytes(posts);
HttpWebRequest myRequest = (HttpWebRequest)WebRequest.Create(url);
myRequest.Method = "GET";
myRequest.ContentType = "text/html;";
myRequest.UserAgent = "Mozilla/5.0 (Windows NT 5.2; rv:14.0) Gecko/20100101 Firefox/14.0.1";
myRequest.Host = "www.aizhan.com";
//myRequest.Headers.Add("Host", "www.aizhan.com");
myRequest.Accept = "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8";
myRequest.KeepAlive = true;

HttpWebResponse myResponse = (HttpWebResponse)myRequest.GetResponse();
StreamReader reader = new StreamReader(myResponse.GetResponseStream(), Encoding.UTF8);
string content = reader.ReadToEnd();
return content;
}
public string GetHTML2(string url) {
WebClient wc = new WebClient();
wc.Credentials = CredentialCache.DefaultCredentials;
byte[] btPageData = wc.DownloadData(url);
string strTargetHtml = Encoding.UTF8.GetString(btPageData);
wc.Dispose();
return strTargetHtml;
}
#endregion