//发送POST请求
var request = (HttpWebRequest)WebRequest.Create(Url);
request.Method = "POST";
request.ContentType = "application/json-rpc";
var byteData = Encoding.UTF8.GetBytes(“POST字符串内容”);
var length = byteData.Length;
request.ContentLength = length;
var writer = request.GetRequestStream();
writer.Write(byteData, 0, length);
writer.Close();
//接收数据
var response = (HttpWebResponse)request.GetResponse();
var responseString = new StreamReader(response.GetResponseStream(), Encoding.GetEncoding("utf-8")).ReadToEnd();