GMT时间转成时间戳

DateTime gtm = new DateTime(1970, 1, 1);

DateTime utc = DateTime.UtcNow.AddHours(8);

int timeStamp = Convert.ToInt32(((TimeSpan)utc.Subtract(gtm)).TotalSeconds);

时间戳转换成时间

int timeStamp = 1326332584;

DateTime d = ((new DateTime(1970,1,1))).AddHours(8);

d = d.AddSeconds(timeStamp );