xml初学者有关问题

xml菜鸟问题
实现一个功能就是 我这里上传一个xml数据给对方服务器的webservice，但是断点调试发现，执行到 var resp = client.UploadData(url, "POST", ms.ToArray()); 这一步就报错： 远程服务器返回错误: (500) 内部服务器错误。

代码如下：
private void Form1_Load(object sender, EventArgs e)
  {
  DataTable data = new DataTable("Project");
  data.Columns.Add("SIM");
  data.Columns.Add("LPN");
  data.Columns.Add("longitude");
  data.Columns.Add("latitude");
  data.Columns.Add("speed");
  data.Columns.Add("direction");
  data.Columns.Add("operationStatus");
  data.Columns.Add("statusDesc");
  data.Columns.Add("gpstime");
  data.Rows.Add(new object[] { "13216654124","", 121.25089, 30.16242, 50, 102, 0, "", "2012-06-27 15:22:52"});  
  using (var ms = new MemoryStream())  
  {  
  // 将DataTable用Xml格式写入流  
  data.WriteXml(ms, XmlWriteMode.WriteSchema);  
  WebClient client = new WebClient();  
  // 定义HttpRequest的Content-Type(xml,json等)  
  client.Headers.Add("Content-Type", "text/xml");
  string url = "http://61.164.66.141:8082/GPSUploadService.asmx?op=SyncGPS";  
  // Send HttpRequest  
  var resp = client.UploadData(url, "POST", ms.ToArray());  
  var strResp = System.Text.Encoding.UTF8.GetString(resp);  
  MessageBox.Show(strResp);  
  }  
  }

是不是我生成的xml有问题，我看了下不是 soap格式，本人菜鸟，如何写才可以变成soap格式的xml呢？

[解决办法]
1. 直接添加ServiceReference，就可以直接以对象方式调用了。

var client = new GPSService.GPSUploadServiceSoapClient();
client.SyncGPS("13216654124","", 121.25089, 30.16242, 50, 102, 0, "", "2012-06-27 15:22:52");

2. 用post如下：

C# code

var client = new WebClient();            client.Headers.Add("SOAPAction: \"http://tempuri.org/SyncGPS\"");            client.Headers.Add("Content-Type: text/xml; charset=utf-8");            var data = new DataTable("SyncGPS");            data.Columns.Add("SIM");            data.Columns.Add("LPN");            data.Columns.Add("longitude");            data.Columns.Add("latitude");            data.Columns.Add("speed");            data.Columns.Add("direction");            data.Columns.Add("operationStatus");            data.Columns.Add("statusDesc");            data.Columns.Add("gpstime");            data.Rows.Add(new object[] { "13216654124", "", 121.25089, 30.16242, 50, 102, 0, "", "2012-06-27 15:22:52" });            using (var sw = new StringWriter())            {                data.WriteXml(sw);                var body = sw.ToString();                var xdoc = new XmlDocument();                xdoc.LoadXml(body);                body = xdoc.FirstChild.InnerXml;                                var xml = "<?xml version=\"1.0\" encoding=\"utf-8\"?>";                xml += "<s:Envelope xmlns:s=\"http://schemas.xmlsoap.org/soap/envelope/\">";                xml += "<s:Body>";                xml += body;                xml += "</s:Body>";                xml += "</s:Envelope>";                var result = client.UploadString("http://61.164.66.141:8082/GPSUploadService.asmx", "POST", xml);                Console.WriteLine(result);            }