C# WebRequest POST上传数据

WebRequest request = WebRequest.Create("http://www.cnsos.net");
// Set the Method property of the request to POST.
request.Method = "POST";
// Create POST data and convert it to a byte array.

System.Xml.XmlDocument xmlpostdata = new System.Xml.XmlDocument();
xmlpostdata.Load(Server.MapPath("XML/20097.xml"));
string postData = HttpUtility.HtmlEncode(xmlpostdata.InnerXml); 


//普通字符串内容
//string postData = "你好，1232355 abdcde";


byte[] byteArray = Encoding.UTF8.GetBytes(postData);
// Set the ContentType property of the WebRequest.
request.ContentType = "application/x-www-form-urlencoded";
// Set the ContentLength property of the WebRequest.
request.ContentLength = byteArray.Length;
// Get the request stream.
Stream dataStream = request.GetRequestStream();
            
// Write the data to the request stream.
dataStream.Write(byteArray, 0, byteArray.Length);
// Close the Stream object.
dataStream.Close();
// Get the response.
WebResponse response = request.GetResponse();
// Display the status.
//Console.WriteLine(((HttpWebResponse)response).StatusDescription);
// Get the stream containing content returned by the server.
dataStream = response.GetResponseStream();
// Open the stream using a StreamReader for easy access.
StreamReader reader = new StreamReader(dataStream);
// Read the content.
string responseFromServer = reader.ReadToEnd();
// Display the content.
//Console.WriteLine(responseFromServer);
// Clean up the streams.
reader.Close();
dataStream.Close();
response.Close();