get UTC Date Time - CSharp System

CSharp examples for System:DateTime UTC

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Description

get UTC Date Time

Demo Code


using System.Threading.Tasks;
using System.Text;
using System.Net.Sockets;
using System.Net;
using System.Linq;
using System.Collections.Generic;
using System;/* w ww .j  a  va2 s.  c  om*/

public class Main{
        public static DateTime getUTCDateTime()
        {
            try
            {
                //default Windows time server
                const string ntpServer = "a.ntp.br";

                // NTP message size - 16 bytes of the digest (RFC 2030)
                var ntpData = new byte[48];

                //Setting the Leap Indicator, Version Number and Mode values
                ntpData[0] = 0x1B; //LI = 0 (no warning), VN = 3 (IPv4 only), Mode = 3 (Client Mode)

                var addresses = Dns.GetHostEntry(ntpServer).AddressList;

                //The UDP port number assigned to NTP is 123
                var ipEndPoint = new IPEndPoint(addresses[0], 123);
                //NTP uses UDP
                var socket = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);

                socket.Connect(ipEndPoint);

                //Stops code hang if NTP is blocked
                socket.ReceiveTimeout = 3000;

                socket.Send(ntpData);
                socket.Receive(ntpData);
                socket.Close();

                //Offset to get to the "Transmit Timestamp" field (time at which the reply 
                //departed the server for the client, in 64-bit timestamp format."
                const byte serverReplyTime = 40;

                //Get the seconds part
                ulong intPart = BitConverter.ToUInt32(ntpData, serverReplyTime);

                //Get the seconds fraction
                ulong fractPart = BitConverter.ToUInt32(ntpData, serverReplyTime + 4);

                //Convert From big-endian to little-endian
                intPart = SwapEndianness(intPart);
                fractPart = SwapEndianness(fractPart);

                var milliseconds = (intPart * 1000) + ((fractPart * 1000) / 0x100000000L);

                //**UTC** time
                var networkDateTime = (new DateTime(1900, 1, 1, 0, 0, 0, DateTimeKind.Utc)).AddMilliseconds((long)milliseconds);

                return networkDateTime.ToLocalTime();
            }
            catch (Exception ex)
            {
                throw new Exception(ex.Message);
            }
        }
}

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