C# 时间处理

using System;
using System.Globalization;

namespace Common
{
    /// <summary>
    /// 时间处理
    /// </summary>
    public class DateTimeCommonHandler
    {
        /// <summary>
        /// 获取时间是一年的第几周
        /// </summary>
        /// <param name="dt"></param>
        /// <returns></returns>
        public int GetWeekNum(DateTime dt)
        {
            GregorianCalendar gc = new GregorianCalendar();
            int weekOfYear = gc.GetWeekOfYear(dt, CalendarWeekRule.FirstDay, DayOfWeek.Monday);
            return weekOfYear;
        }

        /// <summary>
        /// C#获取指定日期时间是当前年度的第几个季度
        /// </summary>
        /// <param name="dt"></param>
        /// <returns></returns>
        public int GetQuarterNum(DateTime dt)
        {
            var mouth = dt.Month;
            int quarter = mouth % 3 == 0 ? mouth / 3 : (mouth / 3 + 1);
            return quarter;
        }

        /// <summary>
        /// 求时间段间隔天数
        /// </summary>
        /// <param name="dateStart"></param>
        /// <param name="dateEnd"></param>
        /// <returns></returns>
        public int DateDiff(DateTime dateStart, DateTime dateEnd)
        {
            DateTime start = Convert.ToDateTime(dateStart.ToShortDateString());
            DateTime end = Convert.ToDateTime(dateEnd.ToShortDateString());
            TimeSpan sp = end.Subtract(start);
            return sp.Days + 1;
        }
    }
}

 获取时间段内的时间：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;

namespace Common
{
    public static class ComputeDateDiff
    {
        public static List<DateTimeDto> GetDateAll(DateTime beginDate, DateTime endDate)
        {
            List<DateTimeDto> list = new List<DateTimeDto>();
            //不跨年的
            if (beginDate.Year == endDate.Year)
            {
                //不跨月的
                if (endDate.Month == beginDate.Month)
                {
                    list.Add(new DateTimeDto() { BeginDate = beginDate, EndDate = endDate });
                }
                //跨月的
                else
                {
                    GetMouth(beginDate, endDate, ref list);
                }
            }
            //跨年的
            else
            {
                for (int i = beginDate.Year; i <= endDate.Year; i++)
                {
                    DateTime startDateTime = new DateTime(i, 1, 1);
                    DateTime endDateTime = new DateTime(i, 12, 31);
                    if (i == beginDate.Year)
                    {
                        startDateTime = beginDate;
                    }
                    else if (i == endDate.Year)
                    {
                        endDateTime = endDate;
                    }

                    GetMouth(startDateTime, endDateTime, ref list);
                }
            }

            return list;
        }

        public static void GetMouth(DateTime beginDate, DateTime endDate, ref List<DateTimeDto> list)
        {
            for (int i = beginDate.Month; i <= endDate.Month; i++)
            {
                if (i == beginDate.Month)
                {
                    list.Add(new DateTimeDto() { BeginDate = beginDate, EndDate = new DateTime(beginDate.Year, beginDate.Month + 1, 1).AddDays(-1) });
                }
                else if (i == endDate.Month)
                {
                    list.Add(new DateTimeDto() { BeginDate = new DateTime(beginDate.Year, i, 1), EndDate = endDate });
                }
                else
                {
                    list.Add(new DateTimeDto() { BeginDate = new DateTime(beginDate.Year, i, 1), EndDate = new DateTime(beginDate.Year, i + 1, 1).AddDays(-1) });
                }
            }
        }
    }
    public class DateTimeDto
    {
        public DateTime BeginDate { get; set; }
        public DateTime EndDate { get; set; }
    }
}