乐趣：获取当前日期所在周

  class Program    {        static void Main(string[] args)        {            int weekOfYear = GetWeekOfYearInt(DateTime.Now);            Console.WriteLine(weekOfYear);            bool IsFlag = GetWeekOfYearBool(DateTime.Now);            Console.WriteLine(IsFlag);            Console.ReadLine();        }----------//利用封装的函数GregorianCalendar         /// <summary>        /// 获取当前日期所在的周        /// </summary>        /// <param name="dt"></param>        /// <returns></returns>        private static int GetWeekOfYearInt(DateTime dt)        {            GregorianCalendar gc = new GregorianCalendar();            int weekOfYear = gc.GetWeekOfYear(dt, CalendarWeekRule.FirstDay, DayOfWeek.Monday);            return weekOfYear;        }----------//将所在日期转化为星期几，并且转换为整型，判断当前日期第一天的日期和输入日期的第一天是否是同一个日期。(默认第一天是星期日）        /// <summary>        /// 获取当前日期所在周        /// </summary>        /// <param name="dt"></param>        /// <returns></returns>        private static bool GetWeekOfYearBool(DateTime dt)        {            bool IsFlag = false;            DateTime newDt = dt.AddDays(-((int)dt.DayOfWeek));            DateTime nowDt = DateTime.Now.AddDays(-(int)DateTime.Now.DayOfWeek);            if (newDt == nowDt)            {                IsFlag = true;            }            return IsFlag;        }    }