日期相关转化 TimeHelper

using System;
using System.Collections.Generic;

namespace MEAS.Common
{
    public class TimeHelper
    {
        //定义一个用于保存静态变量的实例
        private static TimeHelper instance = null;
        //定义一个保证线程同步的标识
        private static readonly object locker = new object();
        //构造函数为私有，使外界不能创建该类的实例
        private TimeHelper() { }
        public static TimeHelper Instance
        {
            get
            {
                if (instance == null)
                {
                    lock (locker)
                    {
                        if (instance == null) instance = new TimeHelper();
                    }
                }
                return instance;
            }
        }

        /// <summary>
        /// 获取固定日期范围内的所有日期，以数组形式返回
        ///DateTime begin1 = DateTime.Parse("2021-05-02");
        ///DateTime end1 = DateTime.Parse("2021-05-12");
        ///List<string> days = TimeHelper.Instance.GetDays(begin1, end1);
        /// </summary>
        /// <param name="startTime"></param>
        /// <param name="endTime"></param>
        public List<string> GetDays(DateTime startTime, DateTime endTime)
        {
            List<string> listDay = new List<string>();
            DateTime dtDay = new DateTime();
            //循环比较，取出日期；
            for (dtDay = startTime; dtDay.CompareTo(endTime) <= 0; dtDay = dtDay.AddDays(1))
            {
                listDay.Add(dtDay.ToString("yyyy-MM-dd"));
            }
            return listDay;
        }

        /// <summary>
        /// 将数字形式的日期转换为标准的日期格式 字符串
        /// </summary>
        /// <param name="date"></param>
        /// <returns></returns>
        public string FamatDate(string date)
        {
            var dt = DateTime.ParseExact(date, "yyyyMM", System.Globalization.CultureInfo.CurrentCulture);
            return dt.ToString("yyyy-MM-dd");
        }

        /// <summary>
        /// 获取时间间隔时长(分钟)
        /// </summary>
        /// <param name="beginTime">开始时间</param>
        /// <param name="endTime">结束时间</param>
        /// <returns></returns>
        public string GetTimeLength(DateTime beginTime, DateTime endTime)
        {
            try
            {
                string TimeLength = string.Empty;
                TimeSpan begin = new TimeSpan(beginTime.Ticks);
                TimeSpan end = new TimeSpan(endTime.Ticks);
                TimeSpan ts = begin.Subtract(end).Duration();

                TimeLength = Convert.ToString(ts.Hours * 60 + ts.Minutes);

                return TimeLength;
            }
            catch { }
            return string.Empty;
        }

        /// <summary>
        /// 计算区间月份
        ///  DateTime begin = DateTime.Parse("2021-08");
        ///  DateTime end = DateTime.Parse("2022-05");
        ///  List<string> months = TimeHelper.Instance.GetMonths(2021, 8, 2022, 5);
        /// </summary>
        /// <param name="startYear">开始年</param>
        /// <param name="startMonth">开始月</param>
        /// <param name="endYear">结束年</param>
        /// <param name="endMonth">结束月</param>
        /// <returns></returns>
        public List<string> GetMonths(int startYear, int startMonth, int endYear, int endMonth)
        {
            List<TimeFormat> list = new List<TimeFormat>();   //计算的区间结果存放在集合
            List<string> ymList = new List<string>();
            if (startYear <= endYear)
            {
                int ComputeYear = endYear - startYear;  //计算开始年和结束年差值
                if (ComputeYear > 0)//跨年情况
                {
                    //循环开始年到结束年
                    for (int i = startYear; i <= startYear + ComputeYear; i++)
                    {
                        if (i == endYear)
                        {
                            for (int lastYear = 1; lastYear <= endMonth; lastYear++)
                            {
                                list.Add(new TimeFormat() { Year = i, Month = lastYear });
                            }
                        }
                        else
                        {
                            if (i == startYear)
                            {
                                for (int lastMonth = startMonth; lastMonth <= 12; lastMonth++)
                                {
                                    list.Add(new TimeFormat() { Year = i, Month = lastMonth });
                                }
                            }
                            else
                            {
                                for (int quyue = 1; quyue <= 12; quyue++)
                                {
                                    list.Add(new TimeFormat() { Year = i, Month = quyue });
                                }
                            }
                        }
                    }
                }
                else //同年情况
                {
                    for (int i = startMonth; i <= endMonth; i++)
                    {
                        list.Add(new TimeFormat() { Year = startYear, Month = i });
                    }
                }

                foreach (var item in list)
                {
                    //发现月份会少0，判断小于10月补0
                    var months = "";
                    if (item.Month < 10) months = "0" + item.Month;
                    else months = Convert.ToString(item.Month);

                    ymList.Add(item.Year + "-" + months);
                }
            }
            return ymList;
        }

        /// <summary>
        /// 获取指定年份区间中的年份
        ///  List<string> years = TimeHelper.Instance.GetYears(2018, 2022);
        /// </summary>
        /// <param name="startYear">开始年份</param>
        /// <param name="endYear">结束年份</param>
        /// <returns></returns>
        public List<string> GetYears(int startYear, int endYear)
        {
            List<string> year = new List<string>();
            for (int i = startYear; i <= endYear; i++)
            {
                year.Add(i.ToString());
            }
            return year;
        }

    }

    /// <summary>
    /// 计算年月区间
    /// </summary>
    public class TimeFormat
    {
        /// <summary>
        /// 年
        /// </summary>
        public int Year { get; set; }
        /// <summary>
        /// 月
        /// </summary>
        public int Month { get; set; }
    }
}