//UTC时间转WINDOWS时间
        public DateTime UTCToDateTime(double l)
        {
            DateTime dtZone = new DateTime(1970, 1, 1, 0, 0, 0);

            dtZone = dtZone.AddSeconds(l);

            return dtZone.ToLocalTime();
        }

        //WINDOWS时间转UTC时间
        public double DateTimeToUTC(DateTime vDate)
        {
            TimeZone tz = TimeZone.CurrentTimeZone;

            vDate = vDate.ToUniversalTime();

            DateTime dtZone = new DateTime(1970, 1, 1, 0, 0, 0);

            return vDate.Subtract(dtZone).TotalSeconds;
        }

//DateTime.FromFileTime 方法

public System.TimeSpan FileAge(long fileCreationTime) {

System.DateTime now = System.DateTime.Now;

try {

System.DateTime fCreationTime = System.DateTime.FromFileTime(fileCreationTime);

System.TimeSpan fileAge = now.Subtract(fCreationTime);

return fileAge;

}

catch (ArgumentOutOfRangeException) {

throw;

}

}

//DateTime.FromFileTimeUtc 方法

//十进制转十六进制,不足补零.

 Convert.ToString(receiveBytes[8], 16).ToString().PadLeft(2, '0')