C#计算时间差值

 /// <summary>
        /// 计算时间差值
        /// </summary>
        /// <param name="DateTime1"></param>
        /// <param name="DateTime2"></param>
        /// <returns></returns>
        private string DateDiff(DateTime DateTime1, DateTime DateTime2)
        {
            string dateDiff = null;
            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";
            dateDiff = ts.Days.ToString() + "-" + ts.Hours.ToString();
            float nYear = ((float)ts.Days) / ;
            //return nYear.ToString();
            return dateDiff;
        }

调用
 DateTime dt1 = new DateTime();
            DateTime dt2 = new DateTime();
            dt1 = DateTime.Now;
            dt2 = DateTime.Parse("2014-1-2 9:00:00");
            MessageBox.Show(DateDiff(dt1,dt2));