WebClient不发布XML

Question

我知道有很多关于Web客户端的问题，但这里有一个新问题。 :) 我想在Web Client的帮助下发布一个XmlDocument，但XML永远不会到达另一端。 Tomcat总是发送回java.lang.NullPointerException。

enter code here
System.Net.WebClient WebClientObj = new System.Net.WebClient();
WebClientObj.Encoding = Encoding.UTF8; ;// System.Text.Encoding.GetEncoding("UTF-8");
WebClientObj.Headers[HttpRequestHeader.ContentType] = "text/xml;charset=utf-8";
ServicePointManager.ServerCertificateValidationCallback +=
   delegate(object sender, X509Certificate certificate, X509Chain chain,
   SslPolicyErrors sslPolicyErrors)
   {
         return true;
   };
byte[] ByteArray = Encoding.UTF8.GetBytes(ecgrr.GetResponse(xmlDoc).InnerXml);
byte[] ResponseBuffer = WebClientObj.UploadData("https://x.x.x.x/abcd/Req", "POST", ByteArray);

OR

string x = WebClientObj.UploadString("https://x.x.x.x/abcd/Req", "POST", ecgrr.GetResponse(xmlDoc).InnerXml);

谢谢。