#region 获取 本周、本月、本季度、本年 的开始时间或结束时间

        /// <summary>

        /// 获取结束时间

        /// </summary>

        /// <param name="TimeType">Week、Month、Season、Year</param>

        /// <param name="now"></param>

        /// <returns></returns>

        public static DateTime? GetTimeStartByType(string TimeType, DateTime now)

        {

            switch (TimeType)

            {

                case "Week":

                    return now.AddDays(-(int)now.DayOfWeek + );

                case "Month":

                    return now.AddDays(-now.Day + );

                case "Season":

                    var time = now.AddMonths( - ((now.Month - ) % ));

                    return time.AddDays(-time.Day + );

                case "Year":

                    return now.AddDays(-now.DayOfYear + );

                default:

                    return null;

            }

        }

        /// <summary>

        /// 获取结束时间

        /// </summary>

        /// <param name="TimeType">Week、Month、Season、Year</param>

        /// <param name="now"></param>

        /// <returns></returns>

        public static DateTime? GetTimeEndByType(string TimeType, DateTime now)

        {

            switch (TimeType)

            {

                case "Week":

                    return now.AddDays( - (int)now.DayOfWeek);

                case "Month":

                    return now.AddMonths().AddDays(-now.AddMonths().Day + ).AddDays(-);

                case "Season":

                    var time = now.AddMonths(( - ((now.Month - ) % ) - ));

                    return time.AddMonths().AddDays(-time.AddMonths().Day + ).AddDays(-);

                case "Year":

                    var time2 = now.AddYears();

                    return time2.AddDays(-time2.DayOfYear);

                default :

                    return null;

            }

        }

        #endregion