如何从时间服务器设置日期/时间

Question

嗨，我正在使用How to Query an NTP Server using C#?的下面的函数从时间服务器获取时间

public  DateTime _MGetNetworkTime()
{
    try
    {
        //default Windows time server
        const string ntpServer = "time.windows.com";

        // 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);

        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 e)
    {
        MessageBox.Show(e.Message);
        return Convert.ToDateTime ("12-31-1900");
    }
}

uint SwapEndianness(ulong x)
{
    return (uint)(((x & 0x000000ff) << 24) +
                   ((x & 0x0000ff00) << 8) +
                   ((x & 0x00ff0000) >> 8) +
                   ((x & 0xff000000) >> 24));
}

上述功能正在工作，但我的问题是：

它没有得到印度时间。假设现在的时间是晚上9:10，函数设置在上午5:30，日期是正确的..

请指点我哪里错了。

谢谢

更新:

我正在设置一个日期时间，例如DateTime a = _MGetNetworkTime();，上面的代码，并将值传递给其他函数，如下所示。

[StructLayout(LayoutKind.Sequential)]
        public struct SYSTEMTIME
        {
            public short wYear;
            public short wMonth;
            public short wDayOfWeek;
            public short wDay;
            public short wHour;
            public short wMinute;
            public short wSecond;
            public short wMilliseconds;
        }
        [DllImport("kernel32.dll", SetLastError = true)]
        public static extern bool SetSystemTime(ref SYSTEMTIME st);

        public  void _MSetSystemDate(short _pYear, short _pMonth, short _pDay, short _pHour = 0, short _pMinute = 0, short _pSecond = 0)
        {
            if (IsUserAdministrator())
            {
                SYSTEMTIME st = new SYSTEMTIME();
                st.wYear = _pYear; // must be short
                st.wMonth = _pMonth;
                st.wDay = _pDay;
                st.wHour = _pHour;
                st.wMinute = _pMinute;
                st.wSecond = _pSecond;
                SetSystemTime(ref st); // invoke this method.
            }
            else
            {
                MessageBox.Show("You have not Windows Administrator Access." + Environment.NewLine + "Please Login Windows with Addministrator Rights.");
            }
        }

Answer 1

我相信这也应该在没有任何互联网连接的情况下起作用。试试看：

private static TimeZoneInfo INDIAN_ZONE = TimeZoneInfo.FindSystemTimeZoneById("India Standard Time");
DateTime indianTime =  TimeZoneInfo.ConvertTimeFromUtc(DateTime.UtcNow, INDIAN_ZONE);