public static class RequestHelper

        {

            public class RequestResult

            {

                public RequestResult(bool requestResult, string resultData)

                {

                    this.Result = requestResult;

                    this.ResultData = resultData;

                }

                public bool Result { get; private set; }

                public string ResultData { get; private set; }

            }

            public static RequestResult Request(string url, string method, string data, Dictionary<string, string> header, string contentType = "application/json;charset=utf-8")

            {

                HttpWebRequest request = null;

                if (url.ToLower().StartsWith("https"))

                {

                    ServicePointManager.ServerCertificateValidationCallback =

                        new System.Net.Security.RemoteCertificateValidationCallback(delegate(object sender, X509Certificate certificate, X509Chain chain, SslPolicyErrors errors)

                        {

                            return true;

                        });

                    request = WebRequest.Create(url) as HttpWebRequest;

                    request.ProtocolVersion = HttpVersion.Version10;

                }

                else

                    request = WebRequest.Create(url) as HttpWebRequest;

                request.Method = method;

                request.AllowAutoRedirect = true;

                request.Proxy = new WebProxy { UseDefaultCredentials = true };

                request.ContentType = contentType;

                foreach (var h in header)

                    request.Headers.Add(h.Key, h.Value);

                try

                {

                    if (data != null && method != "GET")

                    {

                        using (StreamWriter writer = new StreamWriter(request.GetRequestStream()))

                        {

                            writer.Write(data);

                        }

                    }

                    var response = request.GetResponse() as HttpWebResponse;

                    var responseStream = response.GetResponseStream();

                    var reader = new System.IO.StreamReader(responseStream, Encoding.UTF8);

                    string result = reader.ReadToEnd();

                    return new RequestResult(true, result);

                }

                catch (Exception ex)

                {

                    return new RequestResult(false, ex.Message);

                }

            }

        }

var serviceUrl = @"http://192.168.0.xxx:xxxx/webService/xxxx.asmx";

            var header = new Dictionary<string, string>();

            header.Add("SOAPAction", "http://tempuri.org/GetAuthorizationCode");

            var body =

                "<?xml version=\"1.0\" encoding=\"utf-8\"?>"

                + "<soap:Envelope xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\" xmlns:xsd=\"http://www.w3.org/2001/XMLSchema\" xmlns:soap=\"http://schemas.xmlsoap.org/soap/envelope/\">"

                + "  <soap:Body>"

                + "      <GetAuthorizationCode xmlns=\"http://tempuri.org/\">"

                + "          <loginName>180001</loginName>"

                + "          <token>6B17644986B630E9C284C07F4D412C89</token>"

                + "      </GetAuthorizationCode>"

                + "  </soap:Body>"

                + "</soap:Envelope>";

            var result = RequestHelper.Request(serviceUrl, "POST", body, header, "text/xml;charset=utf-8");

            if (!result.Result)

                return;

            var doc = new XmlDocument();

            var namespaceManager = new XmlNamespaceManager(doc.NameTable);

            namespaceManager.AddNamespace("xsi", "http://www.w3.org/2001/XMLSchema-instance");

            namespaceManager.AddNamespace("xsd", "http://www.w3.org/2001/XMLSchema");

            namespaceManager.AddNamespace("soap", "http://schemas.xmlsoap.org/soap/envelope/");

            namespaceManager.AddNamespace("mynamespace", "http://tempuri.org/");

            doc.LoadXml(result.ResultData);

            var resultNode = doc.SelectSingleNode(@"soap:Envelope/soap:Body/mynamespace:GetAuthorizationCodeResponse/mynamespace:GetAuthorizationCodeResult", namespaceManager);

            var resultFlag = bool.Parse(resultNode.InnerText);