计算两个日期的时间间隔

        /// <summary>
        /// 计算两个日期的时间间隔,返回的是时间间隔的日期差的绝对值.
        /// </summary>
        /// <param name="DateTime1">第一个日期和时间</param>
        /// <param name="DateTime2">第二个日期和时间</param>
        /// <returns></returns>
        private string DateDiff(DateTime DateTime1, DateTime DateTime2)
        {
            string dateDiff = null;
            try
            {
                TimeSpan ts1 = new TimeSpan(DateTime1.Ticks);
                TimeSpan ts2 = new TimeSpan(DateTime2.Ticks);
                TimeSpan ts = ts1.Subtract(ts2).Duration();
                dateDiff = ts.Days.ToString();// + "天";
                //        + ts.Hours.ToString() + "小时"
                //        + ts.Minutes.ToString() + "分钟"
                //         + ts.Seconds.ToString() + "秒";
            }
            catch
            {
                dateDiff = "";
            }
            return dateDiff;
        }