C.Net timestamp and time conversion support time zone

 /// <summary>
        /// This time zone date time to timestamp
        /// </summary>
        /// <param name="datetime"> Time </param>
        /// <param name="toMilliseconds"> Is it accurate to milliseconds </param>
        /// <returns></returns>
        public static long ToUnixTimeStamp(this DateTime datetime, bool toMilliseconds = true)
        {
            DateTime beginTimeUtc = new DateTime(1970, 1, 1, 0, 0, 0, 0, DateTimeKind.Utc);// Standard time
            DateTime timeUTC = datetime.ToUniversalTime();// Turn it into time
            TimeSpan ts = (timeUTC - beginTimeUtc);// Subtract the standard start time from the current standard time
            if (toMilliseconds)
            {
                return (Int64)ts.TotalMilliseconds;// Accurate to milliseconds
            }
            return (Int64)ts.TotalSeconds;// Accurate to seconds
        }

        /// <summary>
        /// Time stamp to local time zone date time
        /// </summary>
        /// <param name="TimeStamp"></param>
        /// <param name="toMilliseconds"> Is it accurate to milliseconds </param>
        /// <returns></returns>
        public static DateTime ToDateTime( this long TimeStamp, bool toMilliseconds = true)
        {
            DateTime startTime = new DateTime(1970, 1, 1, 0, 0, 0, 0, DateTimeKind.Utc);// Standard time
            if (toMilliseconds)
            {
                return startTime.AddTicks(TimeStamp * 10000).ToLocalTime();// Standard time to local time
            }
            else
            {
                return startTime.AddTicks(TimeStamp * 10000000).ToLocalTime();// Standard time to local time
            }
        }