C# Net 计算周（可正推和逆推）

C# Net 计算周（可正推和逆推）

拷贝代码（方法）：

        /// <summary>

        /// 计算周

        /// </summary>

        /// <param name="Time">一个时间点，用来计算周（必须有年月日）</param>

        /// <param name="WeekCount">推测的周数量</param>

        /// <param name="Add">是正推（加）还是负推（减）</param>

        /// <param name="ThisWeek">是否包含此时间点所在的周</param>

        /// <returns></returns>

        public static List<TimeWeek> GetTimeWeek(DateTime Time, int WeekCount, bool Add, bool ThisWeek)

        {

            List<TimeWeek> timeWeeks = new List<TimeWeek>();

            TimeWeek week = new TimeWeek();

            week.Week = ConvertWeekOfYear(Time);

            int dayOfTheWeek = (int)Time.DayOfWeek;

            int CountLength = dayOfTheWeek ==  ?  : dayOfTheWeek;

            //如果包含当前周，就加入到返回列表.同时推算的周数减一

            if (ThisWeek)

            {

                DateTime mon = Time.Date.AddDays( - CountLength);//本周一

                DateTime sun = Time.Date.AddDays( - CountLength).AddDays().AddSeconds(-);//本周日

                week.BeginTime = mon;

                week.EndTime = sun;

                timeWeeks.Add(week);

                WeekCount--;

            }

            if (Add)

            {

                for (int i = ; i <= WeekCount; i++)

                {

                    DateTime mon = Time.Date.AddDays( - CountLength + i * );//往前推的周数计算星期一

                    DateTime sun = Time.Date.AddDays( - CountLength + i * ).AddDays().AddSeconds(-);

                    TimeWeek Downweek = new TimeWeek();

                    Downweek.Week = ConvertWeekOfYear(mon);

                    Downweek.BeginTime = mon;

                    Downweek.EndTime = sun;

                    timeWeeks.Add(Downweek);

                }

            }

            else

            {

                for (int i = ; i <= WeekCount; i++)

                {

                    DateTime mon = Time.Date.AddDays( - CountLength - i * );//往回推的周数计算星期一

                    DateTime sun = Time.Date.AddDays( - CountLength - i * ).AddDays().AddSeconds(-);

                    TimeWeek upweek = new TimeWeek();

                    upweek.Week = ConvertWeekOfYear(mon);

                    upweek.BeginTime = mon;

                    upweek.EndTime = sun;

                    timeWeeks.Add(upweek);

                }

            }

            return timeWeeks.OrderBy(t => t.BeginTime).ToList();

        }

        /// <summary>

        /// 返回指定年份的周

        /// </summary>

        /// <param name="time"></param>

        /// <returns></returns>

        public static int ConvertWeekOfYear(DateTime time)

        {

            System.Globalization.GregorianCalendar gc = new System.Globalization.GregorianCalendar();

            return gc.GetWeekOfYear(time, System.Globalization.CalendarWeekRule.FirstDay, DayOfWeek.Monday);

        }

拷贝代码（自定义类）：

    /// <summary>

    /// 时间周

    /// </summary>

    public class TimeWeek

    {

        /// <summary>

        /// 第几周（从开年的1月1日计算）

        /// </summary>

        public int Week { get; set; }

        /// <summary>

        /// 这周的开始时间（一般是周一）

        /// </summary>

        public DateTime BeginTime { get; set; }

        /// <summary>

        /// 这周的结束时间（一般是周日）

        /// </summary>

        public DateTime EndTime { get; set; }

    }