UNIX时间戳与.net日期类的转换(from:http://www.abc188.com/info/html/wangluobiancheng/DotNetBianCheng/20080224/21484.html)
TimeZone.CurrentTimeZone.ToLocalTime(newDateTime(1970,1,1));DateTimedtNow=DateTime.Parse(DateTime.Now.ToString());TimeSpantoNow=dtNow.Subtract