/// <summary>
/// Unix时间戳转成时间
/// </summary>
/// <param name="timeStamp"></param>
/// <returns></returns>
public static DateTime FROM_UNIXTIME(long timeStamp)
{
    return DateTime.Parse("1970-01-01 00:00:00").AddSeconds(timeStamp);
}

/// <summary>
/// 时间转成Unix时间戳
/// </summary>
/// <param name="dateTime"></param>
/// <returns></returns>
public static long UNIX_TIMESTAMP(DateTime dateTime)
{
    return (dateTime.Ticks – DateTime.Parse("1970-01-01 00:00:00").Ticks) / 10000000;
}