C#中如何自定义配置上周和本周起始日来查询业务数据(思路详解)

        /// <summary>
        /// 获得上周、本周配置时间（用于读取数据）
        /// </summary>
        /// <param name="startWeekDay">配置的[周起始日]</param>
        /// <param name="now">当前时间</param>
        /// <returns></returns>
        public (string upper_week_begin, string upper_week_end, string this_week_begin, string this_week_end) GetWeekTimeStr(int startWeekDay, DateTime now)
		{
			if (startWeekDay <  1 || startWeekDay > 7)
			{
                throw new ArgumentOutOfRangeException(nameof(startWeekDay), "startWeekDay must be between 1 and 7.");
            }
            int currentDayOfWeek = (int)now.DayOfWeek;//获取当前日期为星期几
            DateTime currentDate = DateTime.Now.Date; //获取到当前日期
            string upper_week_begin, upper_week_end, this_week_begin, this_week_end;
            //如果配置的星期 大于 当前星期
            if (startWeekDay > currentDayOfWeek || startWeekDay == currentDayOfWeek)
            {
                DayOfWeek week = DayOfWeek.Monday;
                switch (startWeekDay)
                {
                    case 1: week = DayOfWeek.Monday; break;
                    case 2: week = DayOfWeek.Tuesday; break;
                    case 3: week = DayOfWeek.Wednesday; break;
                    case 4: week = DayOfWeek.Thursday; break;
                    case 5: week = DayOfWeek.Friday; break;
                    case 6: week = DayOfWeek.Saturday; break;
                    case 7: week = DayOfWeek.Sunday; break;
                    default:
                        break;
                }
                DateTime lastThursday = GetDayOfWeek(currentDate, week);//本周的开始日期
                DateTime lastWeekSunday = lastThursday.AddDays(6);//本周的结束日期，根据[本周开始日期]往后推6天
                DateTime lastLastThursday = GetDayOfWeek(lastThursday.AddDays(-1), week);//根据本周的开始时间，往前推1天，找到上一周的开始时间
                DateTime lastLastWeekSunday = lastLastThursday.AddDays(6);//上一周的结束时间
                upper_week_begin = lastLastThursday.ToString("yyyy-MM-dd");
                upper_week_end = lastLastWeekSunday.ToString("yyyy-MM-dd");
                this_week_begin = lastThursday.ToString("yyyy-MM-dd");
                this_week_end = lastWeekSunday.ToString("yyyy-MM-dd");
            }
            else
            {
                //返回本周和上周的开始和结束日期
                DateTime thisWeekMonday = GetDayOfWeek(now, DayOfWeek.Monday);//本周的开始日期
				DateTime thisWeekSunday = thisWeekMonday.AddDays(6); //本周的结束日期，根据[本周开始日期]往后推6天
                DateTime lastWeekMonday = thisWeekMonday.AddDays(-7);//根据[本周开始日期]，往前推7天，得到[上周开始时间]
                DateTime lastWeekSunday = thisWeekMonday.AddDays(-1);//根据[本周的开始日期]，往前推1天，得到[上周结束时间]
                upper_week_begin = lastWeekMonday.ToString("yyyy-MM-dd");
                upper_week_end = lastWeekSunday.ToString("yyyy-MM-dd");
                this_week_begin = thisWeekMonday.ToString("yyyy-MM-dd");
                this_week_end = thisWeekSunday.ToString("yyyy-MM-dd");
            }
			return (upper_week_begin, upper_week_end, this_week_begin, this_week_end);
        }
        /// <summary>
        /// 获取上一个指定星期的日期
        /// </summary>
        /// <param name="date"></param>
        /// <param name="targetDayOfWeek"></param>
        /// <returns></returns>
        public static DateTime GetDayOfWeek(DateTime date, DayOfWeek targetDayOfWeek)
        {
            int diff = (7 + (date.DayOfWeek - targetDayOfWeek)) % 7;
            return date.AddDays(-diff).Date;
        }

var item = GetWeekTimeStr(startWeekDay, now);
// 取出数据
if (!string.IsNullOrEmpty(item.upper_week_begin))
{
}
if (!string.IsNullOrEmpty(item.upper_week_end))
{
}
if (!string.IsNullOrEmpty(item.this_week_begin))
{
}
if (!string.IsNullOrEmpty(item.this_week_end))
{
}