ASCIIEncoding encoding = new ASCIIEncoding();
                string postdata = NewXml;
                byte[] data = encoding.GetBytes(postdata);
                HttpWebRequest myRequest = (HttpWebRequest)WebRequest.Create("www.a.aspx");
                myRequest.Method = "POST";
                myRequest.ContentType = ("application/x-www-form-urlencoded");
                myRequest.ContentLength = data.Length;
                Stream newStream = myRequest.GetRequestStream();
                newStream.Write(data, 0, data.Length);
                newStream.Close();我将一个值newxml post到a.aspx  
然后我怎么在a页面用request或者别的方法获取post过来的值