C#底层库--日期扩展类（上周、本周、明年、前年等）

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前言

本专栏为【底层库】，将介绍研发过程中 通用的函数。我们将这些固化的源码，进行重写、规范封装、单元测试、集成测试，从而形成通用化模块库，本专栏称为“底层库”。

作为研发人员的你，并不需要花大量时间，完全掌握“底层库”的含义，你只需要几行调用代码，就可以解决一些项目上碰到的难题。大家有任何问题，可以评论区反馈，私信我。

底层库已实现功能：数据库操作、加解密算法、日志记录、HTTP通信、Socket通信、API前后端交互、邮件发送、文件操作、配置参数存储、Excel导入导出、CSV和DataTable转换、压缩解压、自动编号、Session操作等，

一、底层库介绍

DateTimeExtension.cs日期扩展类，本类的最要用途：用户日期查询，可以设置“下拉框”查找项，通过本底层库，可以自动获取“开始日期”、“结束日期”。
可实现功能：本年、上年、本月、上月、本周、上周、今天、默认日、空日期、下周、下月、下年、昨天、财务月、财务上月、财务下月。
本底层库已经集成封装，以下展示的是库源代码。

二、底层库源码

2.1 创建类DatePeriod.cs日期枚举型

using System;namespace WBF.Utils
{public enum DatePeriod{ThisYear,LastYear,ThisMonth,LastMonth,ThisWeek,LastWeek,Custom,None,NextWeek,NextMonth,NextYear,Yesterday,Today,AccountThisMonth,AccountLastMonth,AccountNextMonth}
}

2.2 创建类StringExt.cs字符串扩展

创建类StringExt.cs，用于字符串拼接，加引号，部分代码。

namespace WBF.Utils
{public static class StringExt{/// <summary>/// 给字符串两边添加单引号（同时会将内部单引号替换成双单引号）/// </summary>/// <param name="S"></param>/// <returns></returns>public static string QuotedStr(this string S){return "'" + S.Replace("'", "''") + "'";}/// <summary>/// 给字符串两边添加括号/// </summary>/// <param name="str">字符串</param>/// <returns>返回带括号的字符串</returns>public static string BracketStr(this string S){return "(" + S + ")";}/// <summary>/// 使用And连接两个SQL条件/// </summary>/// <param name="strCondition1"></param>/// <param name="strCondition2"></param>/// <returns></returns>public static string ConcatSQL(this string S, string strCondition2){if (S.Trim() == "" || strCondition2.Trim() == ""){return S + strCondition2;}return S + " and " + strCondition2;}}
}

2.3 创建类BizHandler.cs

using System;namespace WBF.Utils
{public class BizHandler{public static DateTime GetSettleMonthStartDate(){//return BizHandler.GetSettleMonthStartDate(SysParams.Instance.loginInfo.LoginTime);return BizHandler.GetSettleMonthStartDate(DateTime.Now);}public static DateTime GetSettleMonthStartDate(DateTime a_dtDay){int day = a_dtDay.Day;//string value = SysParams.Instance.SysPar.GetValue("CW_AccoutIsNaturalMonth");string value = "F";if (string.Compare(value, "T", true) == 0){return a_dtDay.Date.AddDays((double)(checked(0 - day + 1)));}//int num = (int)Convert.ToInt16(SysParams.Instance.SysPar.GetValue("month_start_day"));int num = 0;if (num == 0){num = 1;}DateTime dateTime = new DateTime(a_dtDay.Year, a_dtDay.Month, 1);DateTime d = dateTime.AddMonths(1);DateTime d2 = dateTime.AddMonths(-1);TimeSpan timeSpan = d - dateTime;TimeSpan timeSpan2 = dateTime - d2;DateTime dateTime2;if ((double)num > timeSpan2.TotalDays){dateTime2 = new DateTime(dateTime.Year, dateTime.Month, 1);}else if ((double)num > timeSpan.TotalDays){dateTime2 = new DateTime(d2.Year, d2.Month, num);}else{dateTime2 = new DateTime(a_dtDay.Year, a_dtDay.Month, num);}if (dateTime2 > a_dtDay){dateTime2 = dateTime2.AddMonths(-1);}return dateTime2;}}
}

2.4 创建类DateTimeExtension.cs

using System;
using System.Collections.Generic;
using System.Data;
using System.Linq;
using System.Text;
using System.Threading.Tasks;namespace WBF.Utils
{public static class DateTimeExtension{public static void GetSearchDate(DatePeriod a_DatePeriod, out DateTime a_dtStartDate, out DateTime a_dtEndDate){//DateTime dateTime = SysParams.Instance.loginInfo.LoginTime.Date;DateTime dateTime = DateTime.Now.Date;a_dtStartDate = dateTime;a_dtEndDate = dateTime;switch (a_DatePeriod){case DatePeriod.ThisYear:a_dtStartDate = new DateTime(dateTime.Year, 1, 1);a_dtEndDate = new DateTime(dateTime.Year, 12, 31);return;case DatePeriod.LastYear:dateTime = dateTime.AddYears(-1);a_dtStartDate = new DateTime(dateTime.Year, 1, 1);a_dtEndDate = new DateTime(dateTime.Year, 12, 31);return;case DatePeriod.ThisMonth:a_dtStartDate = new DateTime(dateTime.Year, dateTime.Month, 1);a_dtEndDate = a_dtStartDate.AddMonths(1).AddDays(-1.0);return;case DatePeriod.LastMonth:dateTime = dateTime.AddMonths(-1);a_dtStartDate = new DateTime(dateTime.Year, dateTime.Month, 1);a_dtEndDate = a_dtStartDate.AddMonths(1).AddDays(-1.0);return;case DatePeriod.ThisWeek:DateTimeExtension.GetWeekRange(dateTime, out a_dtStartDate, out a_dtEndDate);return;case DatePeriod.LastWeek:dateTime = dateTime.AddDays(-7.0);DateTimeExtension.GetWeekRange(dateTime, out a_dtStartDate, out a_dtEndDate);return;case DatePeriod.Custom:break;case DatePeriod.None:a_dtStartDate = new DateTime(1900, 1, 1);a_dtEndDate = new DateTime(1900, 1, 1);return;case DatePeriod.NextWeek:dateTime = dateTime.AddDays(7.0);DateTimeExtension.GetWeekRange(dateTime, out a_dtStartDate, out a_dtEndDate);return;case DatePeriod.NextMonth:dateTime = dateTime.AddMonths(1);a_dtStartDate = new DateTime(dateTime.Year, dateTime.Month, 1);a_dtEndDate = a_dtStartDate.AddMonths(1).AddDays(-1.0);return;case DatePeriod.NextYear:dateTime = dateTime.AddYears(1);a_dtStartDate = new DateTime(dateTime.Year, 1, 1);a_dtEndDate = new DateTime(dateTime.Year, 12, 31);return;case DatePeriod.Yesterday:a_dtStartDate = dateTime.AddDays(-1.0);a_dtEndDate = dateTime.AddDays(-1.0);return;case DatePeriod.Today:a_dtStartDate = dateTime;a_dtEndDate = dateTime;return;case DatePeriod.AccountThisMonth:{DateTime settleMonthStartDate = BizHandler.GetSettleMonthStartDate();a_dtStartDate = settleMonthStartDate;a_dtEndDate = settleMonthStartDate.AddMonths(1).AddDays(-1.0);return;}case DatePeriod.AccountLastMonth:{DateTime settleMonthStartDate = BizHandler.GetSettleMonthStartDate();a_dtStartDate = settleMonthStartDate.AddMonths(-1);a_dtEndDate = settleMonthStartDate.AddDays(-1.0);return;}case DatePeriod.AccountNextMonth:{DateTime settleMonthStartDate = BizHandler.GetSettleMonthStartDate();a_dtStartDate = settleMonthStartDate.AddMonths(1);a_dtEndDate = settleMonthStartDate.AddDays(-1.0).AddMonths(2);break;}default:return;}}//public static DateTime GetServerDate()//{//    FetchData fetchData = new FetchData();//    fetchData.InitSQL("select getdate() as d", false);//    if (fetchData.Fetch())//    {//        DataTable dataTable = fetchData.Data.Tables[0];//        return Convert.ToDateTime(dataTable.Rows[0][0]).Date;//    }//    throw new Abort();//}//public static DateTime GetServerTime()//{//    FetchData fetchData = new FetchData();//    fetchData.InitSQL("select getdate() as d", false);//    if (fetchData.Fetch())//    {//        DataTable dataTable = fetchData.Data.Tables[0];//        return Convert.ToDateTime(dataTable.Rows[0][0]);//    }//    throw new Abort();//}public static void GetWeekRange(DateTime a_dTime, out DateTime a_dStartDay, out DateTime a_dEndDay){checked{try{int num = (int)a_dTime.DayOfWeek;num = ((num == 0) ? 7 : num);a_dStartDay = a_dTime.AddDays((double)(0 - (num - 1))).Date;a_dEndDay = a_dTime.AddDays((double)(7 - num)).Date;}catch (Exception ex){throw new Exception(ex.Message);}}}public static DateTime AddWeek(this DateTime a_Date, int a_WeekCount, ref int a_intYear, ref int a_intWeek){DateTime dateTime = a_Date.AddDays((double)(checked(a_WeekCount * 7)));DateTimeUtils.GetWeekIndex(dateTime, ref a_intYear, ref a_intWeek);return dateTime;}public static DateTime AddWeek(this DateTime a_Date, int a_WeekCount, ref DateTime a_dStart, ref DateTime a_dEnd){DateTime dateTime = a_Date.AddDays((double)(checked(a_WeekCount * 7)));DateTimeUtils.GetWeekRange(dateTime, ref a_dStart, ref a_dEnd);return dateTime;}//public static bool GetYearAndWeekIndex(DateTime a_dtDatetime, ref int a_intYear, ref int a_intWeek)//{//    FetchData fetchData = new FetchData();//    string a_strSQL = string.Concat(new string[]//    {//        "select datepart(yyyy,",//        a_dtDatetime.ToShortDateString().QuotedStr(),//        ") as sys_year,  datepart(wk,",//        a_dtDatetime.ToShortDateString().QuotedStr(),//        ") as sys_week"//    });//    fetchData.InitSQL(a_strSQL, false);//    if (fetchData.Fetch())//    {//        a_intYear = (int)Convert.ToInt16(fetchData.Data.Tables[0].Rows[0]["sys_year"]);//        a_intWeek = (int)Convert.ToInt16(fetchData.Data.Tables[0].Rows[0]["sys_week"]);//        return true;//    }//    a_intYear = 0;//    a_intWeek = 0;//    return false;//}}
}

2.5 创建类DateTimeUtils.cs

using System;namespace WBF.Utils
{public class DateTimeUtils{public static string GetWeekDay(string strDate){string weekDay;try{DateTime a_dtDateTime = Convert.ToDateTime(strDate);weekDay = DateTimeUtils.GetWeekDay(a_dtDateTime);}catch (Exception ex){throw new Exception(ex.Message);}return weekDay;}public static string GetWeekDay(DateTime a_dtDateTime){string weekDay;try{int dayOfWeek = (int)a_dtDateTime.DayOfWeek;weekDay = DateTimeUtils.GetWeekDay(dayOfWeek);}catch (Exception ex){throw new Exception(ex.Message);}return weekDay;}public static int GetMaxWeekOfYear(int a_intYear){int result;try{DateTime minValue = DateTime.MinValue;DateTime minValue2 = DateTime.MinValue;DateTimeUtils.GetStartAndEndDate(a_intYear, ref minValue, ref minValue2);result = checked(minValue2.Subtract(minValue).Days + 1) / 7;}catch (Exception ex){throw new Exception(ex.Message);}return result;}public static int GetMaxWeekOfYear(DateTime dTime){int maxWeekOfYear;try{maxWeekOfYear = DateTimeUtils.GetMaxWeekOfYear(dTime.Year);}catch (Exception ex){throw new Exception(ex.Message);}return maxWeekOfYear;}public static void GetWeekIndex(DateTime dTime, ref int a_intYear, ref int a_intWeek){checked{try{DateTime minValue = DateTime.MinValue;DateTime minValue2 = DateTime.MinValue;DateTimeUtils.GetStartAndEndDate(dTime.Year, ref minValue, ref minValue2);if (dTime > minValue2){a_intYear = dTime.Year + 1;a_intWeek = 1;}else if (dTime < minValue){a_intYear = dTime.Year - 1;a_intWeek = DateTimeUtils.GetMaxWeekOfYear(a_intYear);}else{int num = (int)dTime.DayOfWeek;num = ((num == 0) ? 7 : num);DateTime dateTime = dTime.AddDays((double)(0 - (num - 1)));a_intYear = dTime.Year;a_intWeek = dateTime.Subtract(minValue).Days / 7 + 1;}}catch (Exception ex){throw new Exception(ex.Message);}}}private static void GetStartAndEndDate(int a_intYear, ref DateTime a_dtStart, ref DateTime a_dtEnd){DateTime dateTime = new DateTime(a_intYear, 1, 1);DateTime dateTime2 = new DateTime(a_intYear, 12, 31);int num = (int)dateTime.Date.DayOfWeek;int num2 = (int)dateTime2.Date.DayOfWeek;if (num == 0){num = 7;}if (num2 == 0){num2 = 7;}checked{if (num > 4){a_dtStart = dateTime.AddDays((double)(7 - num + 1));}else{a_dtStart = dateTime.AddDays((double)(0 - (num - 1)));}if (num2 < 4){a_dtEnd = dateTime2.AddDays((double)(0 - num2));return;}a_dtEnd = dateTime2.AddDays((double)(7 - num2));}}public static void GetWeekIndex(string a_strDate, ref int a_intYear, ref int a_intWeek){try{DateTime dTime = Convert.ToDateTime(a_strDate);DateTimeUtils.GetWeekIndex(dTime, ref a_intYear, ref a_intWeek);}catch (Exception ex){throw new Exception(ex.Message);}}public static string GetWeekRange(DateTime dTime, ref DateTime a_dStartDay, ref DateTime a_dEndDay){checked{string result;try{int num = (int)dTime.DayOfWeek;num = ((num == 0) ? 7 : num);a_dStartDay = dTime.AddDays((double)(0 - (num - 1))).Date;a_dEndDay = dTime.AddDays((double)(7 - num)).Date;result = DateTimeUtils.WeekRangeToString(a_dStartDay, a_dEndDay);}catch (Exception ex){throw new Exception(ex.Message);}return result;}}public static string GetWeekRange(int a_intYear, int a_intWeekIndex, ref DateTime a_dtStartDay, ref DateTime a_dtEndDay){string result;try{if (a_intWeekIndex < 1){throw new Exception("周数必须大于0!");}DateTime minValue = DateTime.MinValue;DateTime minValue2 = DateTime.MinValue;DateTimeUtils.GetStartAndEndDate(a_intYear, ref minValue, ref minValue2);int maxWeekOfYear = DateTimeUtils.GetMaxWeekOfYear(a_intYear);if (a_intWeekIndex > maxWeekOfYear){throw new Exception(a_intYear.ToString() + "年没有第" + a_intWeekIndex.ToString() + "周");}a_dtStartDay = minValue.AddDays((double)(checked((a_intWeekIndex - 1) * 7))).Date;a_dtEndDay = a_dtStartDay.AddDays(6.0).Date;result = DateTimeUtils.WeekRangeToString(a_dtStartDay, a_dtEndDay);}catch (Exception ex){throw new Exception(ex.Message);}return result;}private static string WeekRangeToString(DateTime weekRangeStart, DateTime weekRangeEnd){string str = weekRangeStart.ToString("yyyy/MM/dd");string str2 = weekRangeEnd.ToString("yyyy/MM/dd");return str + "～" + str2;}public static string GetWeekDay(int index){string result = string.Empty;switch (index){case 0:result = "星期日";break;case 1:result = "星期一";break;case 2:result = "星期二";break;case 3:result = "星期三";break;case 4:result = "星期四";break;case 5:result = "星期五";break;case 6:result = "星期六";break;}return result;}}
}

三、调用方法

我这里写了一个测试用例，我们看一下效果。

        static void Main(string[] args){DateTime l_dtstart;DateTime l_dtend;DateTimeExtension.GetSearchDate(DatePeriod.Today, out l_dtstart, out l_dtend);DateTimeExtension.GetSearchDate(DatePeriod.LastWeek, out l_dtstart, out l_dtend);DateTimeExtension.GetSearchDate(DatePeriod.ThisWeek, out l_dtstart, out l_dtend);DateTimeExtension.GetSearchDate(DatePeriod.Yesterday, out l_dtstart, out l_dtend);}

三、项目案列