/// <summary>        /// 获取时间差        /// </summary>        /// <param name="dtOld">要减的时间</param>        /// <param name="dtNow">大的时间</param>        /// <returns></returns>       public static string  GetDateDiff(DateTime dtOld,DateTime dtNow)       {           TimeSpan tsOld = new TimeSpan(dtOld.Ticks);           TimeSpan tsNow= new TimeSpan(dtNow .Ticks );           TimeSpan datediff = tsOld.Subtract(tsNow).Duration();           if (Convert.ToInt32(datediff.Days) <=0)           {               if (Convert.ToInt32(datediff.Hours) <= 0)               {                   if (Convert.ToInt32(datediff.Minutes) > 0)                   {                       return datediff.Minutes.ToString() + "分钟前";                   }                   else                   {                       return "";                   }               }               else               {                   return datediff.Hours .ToString() + "小时前";               }           }           else            {               if (Convert.ToInt32(datediff.Days) < 365)               {                   return datediff.Days.ToString() + "天前";               }               else               {                   int year = Convert.ToInt32(datediff.Days) / 365;                   return year .ToString ()+ "年前";               }           }       }