public class CalculationTimes
    {
        public static string CalculationTime(DateTime Starttime)
        {
            string timeString = "";
            DateTime EndTime = DateTime.Now;
            if (EndTime < Starttime)
                return "开始时间不能大于当前时间";
            TimeSpan span = EndTime - Starttime;
            if (span.Days > 365)
                timeString = (span.Days / 365).ToString() + "年前";
            else if (span.Days > 30)
                timeString = (span.Days / 30).ToString() + "个月前";
            else if (span.Days > 0)
                timeString = span.Days.ToString() + "天前";
            else if (span.Hours > 0)
                timeString = span.Hours.ToString() + "小时前";
            else if (span.Minutes > 0)
                timeString = span.Minutes.ToString() + "分钟前";
            else if (span.Seconds > 0)
                timeString = span.Seconds.ToString() + "秒前";
            else
                timeString = "刚刚";
            return timeString;
        }
    }