c# 计算两日期的工作时间间隔(排除非工作日)及计算下一个工作时间点.

一个日期段如工作时间为 8:00 至 17：00

public class TimeHelper
    {

        /// <summary>
        /// 计算时间间隔
        /// </summary>
        /// <param name="tsStart"></param>
        /// <param name="tsEnd"></param>
        /// <param name="time_start"></param>
        /// <param name="time_end"></param>
        /// <returns></returns>
        public static TimeSpan GetTimeSpan(TimeSpan tsStart, TimeSpan tsEnd, TimeSpan time_start, TimeSpan time_end)
        {
            if (tsStart > tsEnd)
                return new TimeSpan();

            if (tsEnd < time_start)
                return new TimeSpan();

            if (tsStart > time_end)
                return new TimeSpan();

            if (tsStart >= time_start && tsStart <= time_end)
                time_start = tsStart;

            if (tsEnd <= time_end && tsEnd >= time_start)
                time_end = tsEnd;

            return time_end - time_start;
        }
        /// <summary>
        /// 获取两日期的工作时间间隔
        /// </summary>
        /// <param name="dtStart"></param>
        /// <param name="dtEnd"></param>
        /// <param name="time_start"></param>
        /// <param name="time_end"></param>
        /// <returns></returns>
        public static TimeSpan GetDateTimeSpan(DateTime dtStart, DateTime dtEnd, TimeSpan time_start, TimeSpan time_end)
        {
            if (dtStart.Date == dtEnd.Date) //如果是同一天
            {
                if (IsWorkDay(dtStart))
                    return GetTimeSpan(dtStart.TimeOfDay, dtEnd.TimeOfDay, time_start, time_end);
                else
                    return new TimeSpan();
            }
            //如果不是同一天 计算天数减去1 乘以标准时长 加上分别计算开始开数和结束天数
            double days = dtEnd.Date.Subtract(dtStart.Date).TotalDays - ;

            TimeSpan startTimeSpan;
            if (IsWorkDay(dtStart))
                startTimeSpan = GetTimeSpan(dtStart.TimeOfDay, new TimeSpan(, , ), time_start, time_end);//开始天
            else
                startTimeSpan = new TimeSpan();

            TimeSpan endTimeSpan;
            if (IsWorkDay(dtEnd))
                endTimeSpan = GetTimeSpan(new TimeSpan(, , ), dtEnd.TimeOfDay, time_start, time_end);//结束天
            else
                endTimeSpan = new TimeSpan();

            TimeSpan totalTimeSpan = startTimeSpan + endTimeSpan; //总值

            TimeSpan preTimeSpan = time_end - time_start;
            for (int i = ; i <=days; i++)
            {
                if (IsWorkDay(dtStart.AddDays(i)))
                    totalTimeSpan += preTimeSpan; //添加间隔天
            }

            return totalTimeSpan;
        }
        /// <summary>
        /// 判断是否为工作日
        /// </summary>
        /// <param name="dt"></param>
        /// <returns></returns>
        public static bool IsWorkDay(DateTime dt)
        {
            //先从日期表中，查找不是上班时间，如果不是直接返回 false ，如果是，直接返回 true。
            //如果在日期表中，找不到，则查找定义的日历，依据日历定义的周末时间来定义是否为工作日。
            //获取日历中不上班的标准周末时间,判断是不是上班时间
            if (dt.DayOfWeek == DayOfWeek.Sunday || dt.DayOfWeek == DayOfWeek.Saturday)
                return false;
            else
                return true;
        }
        /// <summary>
        /// 给定时间点加上时间间隔后得出新的时间
        /// </summary>
        /// <param name="startDate"></param>
        /// <param name="exTimeSpan"></param>
        /// <param name="time_start"></param>
        /// <param name="time_end"></param>
        /// <returns></returns>
        public static DateTime GetDateTime(DateTime startDate, TimeSpan exTimeSpan, TimeSpan time_start, TimeSpan time_end)
        {
            TimeSpan t_span = exTimeSpan;
            //初始到工作日
            while (!IsWorkDay(startDate))
                startDate = startDate.AddDays();
            //初始到起始时间
            if (startDate.TimeOfDay < time_start)
                startDate = startDate - startDate.TimeOfDay + time_start;

            if (startDate.TimeOfDay > time_end)
            {
                startDate = startDate.AddDays();
                startDate = startDate - startDate.TimeOfDay + time_start;

                //初始到工作日
                while (!IsWorkDay(startDate))
                    startDate = startDate.AddDays();
            }
            //计算本天结束剩余多少天
            TimeSpan tmpTs = GetTimeSpan(startDate.TimeOfDay, time_end, time_start, time_end);

            //剩余时长
            exTimeSpan = exTimeSpan - tmpTs;
            //如果计算后剩余小于零 直接返回
            if (exTimeSpan < new TimeSpan())
                return startDate + t_span;

            //如果计算后大于零，继续新增1天.
            TimeSpan preDayTimeSpan = time_end - time_start;
            do
            {
                do
                {
                    startDate = startDate.AddDays();
                } while (!IsWorkDay(startDate));

                if (exTimeSpan > preDayTimeSpan)
                    exTimeSpan -= preDayTimeSpan;
                else
                    break;

            } while (exTimeSpan > new TimeSpan());

            startDate = startDate - startDate.TimeOfDay + time_start; //把计算得出的当天值为初始时间如早上8:00

            return startDate + exTimeSpan;
        }
    }

二段工作时间：如 8:00至12:00   13:00 至17:00

    public class TimeHelper2
    {
        public static TimeSpan GetDateTimeSpan(DateTime dtStart, DateTime dtEnd, TimeSpan time_start, TimeSpan time_end, TimeSpan time_start2, TimeSpan time_end2)
        {
            if (dtStart.Date == dtEnd.Date) //如果是同一天
            {
                if (IsWorkDay(dtStart))
                    return GetTimeSpan(dtStart.TimeOfDay, dtEnd.TimeOfDay, time_start, time_end, time_start2, time_end2);
                else
                    return new TimeSpan();
            }
            //如果不是同一天 计算天数减去1 乘以标准时长 加上分别计算开始开数和结束天数
            double days = dtEnd.Date.Subtract(dtStart.Date).TotalDays - ;

            TimeSpan startTimeSpan;
            if (IsWorkDay(dtStart))
                startTimeSpan = GetTimeSpan(dtStart.TimeOfDay, new TimeSpan(, , ), time_start, time_end, time_start2, time_end2);//开始天
            else
                startTimeSpan = new TimeSpan();

            TimeSpan endTimeSpan;
            if (IsWorkDay(dtEnd))
                endTimeSpan = GetTimeSpan(new TimeSpan(, , ), dtEnd.TimeOfDay, time_start, time_end, time_start2, time_end2);//结束天
            else
                endTimeSpan = new TimeSpan();

            TimeSpan totalTimeSpan = startTimeSpan + endTimeSpan; //总值

            TimeSpan preTimeSpan = GetTimeSpan(new TimeSpan(, , ), new TimeSpan(, , ), time_start, time_end, time_start2, time_end2);//开始天
            for (int i = ; i <= days; i++)
            {
                if (IsWorkDay(dtStart.AddDays(i)))
                    totalTimeSpan += preTimeSpan; //添加间隔天
            }

            return totalTimeSpan;
        }

        /// <summary>
        /// 判断是否为工作日
        /// </summary>
        /// <param name="dt"></param>
        /// <returns></returns>
        public static bool IsWorkDay(DateTime dt)
        {
            //先从日期表中，查找不是上班时间，如果不是直接返回 false ，如果是，直接返回 true。
            //如果在日期表中，找不到，则查找定义的日历，依据日历定义的周末时间来定义是否为工作日。
            //获取日历中不上班的标准周末时间,判断是不是上班时间
            if (dt.DayOfWeek == DayOfWeek.Sunday || dt.DayOfWeek == DayOfWeek.Saturday)
                return false;
            else
                return true;
        }

        //同一天获取
        public static TimeSpan GetTimeSpan(TimeSpan tsStart, TimeSpan tsEnd, TimeSpan time_start, TimeSpan time_end, TimeSpan time_start2, TimeSpan time_end2)
        {

            //判断 开始时间
            if (tsStart < time_start)
            {
                //标准开始时间不变
                //start1 不变
                //start2 不变
            }
            else if (tsStart >= time_start && tsStart <= time_end)
            {
                //标准开始= dtStart
                time_start = tsStart;
                //start1 变
                //start2 不变
            }
            else if (tsStart > time_end && tsStart < time_start2)
            {
                time_start = time_end;
                //start1 变
                //start2 不变
            }
            else if (tsStart >= time_start2 && tsStart <= time_end2)
            {
                time_start = time_end;
                time_start2 = tsStart;
                //start1 变
                //start2 变
            }
            else if (tsStart > time_end2)
            {
                time_start = time_end;
                time_start2 = time_end2;
                //start1 变
                //start2 变
            }

            //判断 结束时间
            if (tsEnd < time_start)
            {
                //标准开始时间不变
                time_end = time_start;
                time_end2 = time_start2;
                //time_end 变
                //time_end2变
            }
            else if (tsEnd >= time_start && tsEnd <= time_end)
            {
                time_end = tsEnd;
                time_end2 = time_start2;
                //time_end 变
                //time_end2变
            }
            else if (tsEnd > time_end && tsEnd < time_start2)
            {
                time_end2 = time_start2;
                //time_end2 不变
                //time_end1变
            }
            else if (tsEnd >= time_start2 && tsEnd <= time_end2)
            {
                time_end2 = tsEnd;
                //time_end 不变
                //time_end2变
            }
            else if (tsEnd > time_end2)
            {
                //time_end 不变
                //time_end2不变
            }

            return (time_end - time_start) + (time_end2 - time_start2);
        }
    }

三个时间段的 如工作时间为：//8:30-12:00 13.30-17.30 18.00-21.00

    public class TimeHelper3
    {

        public static TimeSpan GetDateTimeSpan(DateTime dtStart, DateTime dtEnd, TimeSpan time_start, TimeSpan time_end, TimeSpan time_start2, TimeSpan time_end2, TimeSpan time_start3, TimeSpan time_end3)
        {
            if (dtStart.Date == dtEnd.Date) //如果是同一天
            {
                if (IsWorkDay(dtStart))
                    return GetTimeSpan(dtStart.TimeOfDay, dtEnd.TimeOfDay, time_start, time_end, time_start2, time_end2, time_start3, time_end3);
                else
                    return new TimeSpan();
            }
            //如果不是同一天 计算天数减去1 乘以标准时长 加上分别计算开始开数和结束天数
            double days = dtEnd.Date.Subtract(dtStart.Date).TotalDays - ;

            TimeSpan startTimeSpan;
            if (IsWorkDay(dtStart))
                startTimeSpan = GetTimeSpan(dtStart.TimeOfDay, new TimeSpan(, , ), time_start, time_end, time_start2, time_end2, time_start3, time_end3);//开始天
            else
                startTimeSpan = new TimeSpan();

            TimeSpan endTimeSpan;
            if (IsWorkDay(dtEnd))
                endTimeSpan = GetTimeSpan(new TimeSpan(, , ), dtEnd.TimeOfDay, time_start, time_end, time_start2, time_end2, time_start3, time_end3);//结束天
            else
                endTimeSpan = new TimeSpan();

            TimeSpan totalTimeSpan = startTimeSpan + endTimeSpan; //总值

            TimeSpan preTimeSpan = GetTimeSpan(new TimeSpan(, , ), new TimeSpan(, , ), time_start, time_end, time_start2, time_end2, time_start3, time_end3);//开始天
            for (int i = ; i <= days; i++)
            {
                if (IsWorkDay(dtStart.AddDays(i)))
                    totalTimeSpan += preTimeSpan; //添加间隔天
            }

            return totalTimeSpan;
        }

        /// <summary>
        /// 判断是否为工作日
        /// </summary>
        /// <param name="dt"></param>
        /// <returns></returns>
        public static bool IsWorkDay(DateTime dt)
        {
            //先从日期表中，查找不是上班时间，如果不是直接返回 false ，如果是，直接返回 true。
            //如果在日期表中，找不到，则查找定义的日历，依据日历定义的周末时间来定义是否为工作日。
            //获取日历中不上班的标准周末时间,判断是不是上班时间
            if (dt.DayOfWeek == DayOfWeek.Sunday || dt.DayOfWeek == DayOfWeek.Saturday)
                return false;
            else
                return true;
        }
        //同一天获取
        public static TimeSpan GetTimeSpan(TimeSpan tsStart, TimeSpan tsEnd, TimeSpan time_start, TimeSpan time_end, TimeSpan time_start2, TimeSpan time_end2, TimeSpan time_start3, TimeSpan time_end3)
        {
            //判断 开始时间
            if (tsStart < time_start)
            {
                //标准开始时间不变
                //start1 不变
                //start2 不变
                //start3 不变
            }
            else if (tsStart >= time_start && tsStart <= time_end)
            {
                //标准开始= dtStart
                time_start = tsStart;
                //start1 变
                //start2 不变
                //start3 不变
            }
            else if (tsStart > time_end && tsStart < time_start2)
            {
                time_start = time_end;
                //start1 变
                //start2 不变
                //start3 不变
            }
            else if (tsStart >= time_start2 && tsStart <= time_end2)
            {
                time_start = time_end;
                time_start2 = tsStart;
                //start1 变
                //start2 变
                //start3 不变
            }
            else if (tsStart > time_end2 && tsStart < time_start3)
            {
                time_start = time_end;
                time_start2 = time_end2;
                //start1 变
                //start2 变
                //start3 不变
            }
            else if (tsStart >= time_start3 && tsStart <= time_end3)
            {
                time_start = time_end;
                time_start2 = time_end2;
                time_start3 = tsStart;
                //start1 变
                //start2 变
                //start3 变
            }
            else if (tsStart > time_end3)
            {
                time_start = time_end;
                time_start2 = time_end2;
                time_start3 = time_end3;
            }

            //判断 结束时间
            if (tsEnd < time_start)
            {
                //标准开始时间不变
                time_end = time_start;
                time_end2 = time_start2;
                time_end3 = time_start3;
                //time_end 变
                //time_end2变
                //time_end3变
            }
            else if (tsEnd >= time_start && tsEnd <= time_end)
            {
                time_end = tsEnd;
                time_end2 = time_start2;
                time_end3 = time_start3;
                //time_end 变
                //time_end2变
                //time_end3变
            }
            else if (tsEnd > time_end && tsEnd < time_start2)
            {
                time_end2 = time_start2;
                time_end3 = time_start3;
                //time_end1 不变
                //time_end2变
                //time_end3变
            }
            else if (tsEnd >= time_start2 && tsEnd <= time_end2)
            {
                time_end2 = tsEnd;
                time_end3 = time_start3;
                //time_end 不变
                //time_end2变
                //time_end3变
            }
            else if (tsEnd > time_end2 && tsEnd < time_start3)
            {
                time_end3 = time_start3;
                //time_end 不变
                //time_end2不变
                //time_end3变
            }
            else if (tsEnd >= time_start3 && tsEnd <= time_end3)
            {
                time_end3 = tsEnd;
                //time_end 不变
                //time_end2不变
                //time_end3变
            }
            else if (tsEnd > time_end3)
            {
                //time_end 不变
                //time_end2不变
                //time_end3不变
            }

            return (time_end - time_start) + (time_end2 - time_start2) + (time_end3 - time_start3);
        }
    }

使用方法：

        static void Main(string[] args)
        {
            DateTime dt = Convert.ToDateTime("2014-04-17 08:00");
            DateTime dt2 = Convert.ToDateTime("2014-04-21 08:00");

            TimeSpan tsStar1 = new TimeSpan(, , );
            TimeSpan tsEnd1 = new TimeSpan(, , );

            TimeSpan tsStar2 = new TimeSpan(, , );
            TimeSpan tsEnd2 = new TimeSpan(, , );

            TimeSpan tsStar3 = new TimeSpan(, , );
            TimeSpan tsEnd3 = new TimeSpan(, , );

            //8:30-12:00 13.30-17.30 18.00-21.00

            TimeSpan ts1 = TimeHelper.GetDateTimeSpan(dt, dt2, tsStar1, tsEnd1);

            TimeSpan ts2 = TimeHelper2.GetDateTimeSpan(dt, dt2, tsStar1, tsEnd1, tsStar2, tsEnd2);

            TimeSpan ts3 = TimeHelper3.GetDateTimeSpan(dt, dt2, tsStar1, tsEnd1, tsStar2, tsEnd2, tsStar3, tsEnd3);

            Console.WriteLine("一阶段:{0}天 {1}小时，{2}分，{3}秒", ts1.Days, ts1.Hours, ts1.Minutes, ts1.Seconds);
            Console.WriteLine("两阶段:{0}天 {1}小时，{2}分，{3}秒", ts2.Days, ts2.Hours, ts2.Minutes, ts2.Seconds);
            Console.WriteLine("三阶段:{0}天 {1}小时，{2}分，{3}秒", ts3.Days, ts3.Hours, ts3.Minutes, ts3.Seconds);

            Console.ReadLine();

        }