C#访问URL并获取文件内容（Web）

string rXml = string.Empty;
        HttpWebRequest myHttpWebRequest = System.Net.WebRequest.Create(url) as HttpWebRequest;
        myHttpWebRequest.KeepAlive = false;
        myHttpWebRequest.AllowAutoRedirect = false;
        myHttpWebRequest.UserAgent = "Mozilla/5.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; .NET CLR 2.0.50727)";
        myHttpWebRequest.Timeout = 10000;
        myHttpWebRequest.ContentType = "application/x-www-form-urlencoded;charset=utf-8";
        using (HttpWebResponse res = (HttpWebResponse)myHttpWebRequest.GetResponse())
        {
            if (res.StatusCode == HttpStatusCode.OK || res.StatusCode == HttpStatusCode.PartialContent)//返回为200或206
            {
                string dd = res.ContentEncoding;
                System.IO.Stream strem = res.GetResponseStream();
                System.IO.StreamReader r = new System.IO.StreamReader(strem);
                rXml = r.ReadToEnd();
            }
        }
        Response.Write(rXml);