如何计算两日期之前的天数(附不完善的代码)？

          private static string[] nearDayName = { "三天前", "前天", "昨天", "今天", "明天", "后天", "三天后" };

      public static String ToNearDayName(DateTime dt)

        {

            int days = (dt.Year * 365 + dt.DayOfYear) - (DateTime.Now.Year * 365 + DateTime.Now.DayOfYear);

            return ToNearDayName(days);

        }



        public static String ToNearDayName(int days)

        {

            days += 3;

            days = Math.Max(days, 0);

            days = Math.Min(days, 6);

            return nearDayName[days];

        }