unix 时间戳 和 Csharp 时间的换算，在秒与毫秒上耽误了不少功夫

       public static DateTime ConvertStampToTime(long timeStamp)
        {
            if (timeStamp.ToString().Length == 13)
            {
                timeStamp = timeStamp / 1000;
            }
            DateTime dtStart = TimeZone.CurrentTimeZone.ToLocalTime(new DateTime(1970, 1, 1));
            long lTime = long.Parse(timeStamp + "0000000");
            TimeSpan toNow = new TimeSpan(lTime);
            return dtStart.Add(toNow);
        }  
        public static long ConvertTimeToStamp(System.DateTime time)
        {
            return (time.ToUniversalTime().Ticks - 621355968000000000) / 10000;
        }