zoukankan      html  css  js  c++  java
  • 所在周的第一天

    using System;  
    using System.Collections.Generic;  
    using System.Linq;  
    using System.Text;  
      
    namespace WyfClass  
    {  
    public class tools  
    {  
    /// <summary>  
    /// 得到本周第一天(以星期天为第一天)  
    /// </summary>  
    /// <param name="datetime"></param>  
    /// <returns></returns>  
    public DateTime GetWeekFirstDaySun(DateTime datetime)  
    {  
        //星期天为第一天  
        int weeknow = Convert.ToInt32(datetime.DayOfWeek);  
        int daydiff = (-1) * weeknow;  
      
        //本周第一天  
        string FirstDay = datetime.AddDays(daydiff).ToString("yyyy-MM-dd");  
        return Convert.ToDateTime(FirstDay);  
    }  
      
    /// <summary>  
    /// 得到本周第一天(以星期一为第一天)  
    /// </summary>  
    /// <param name="datetime"></param>  
    /// <returns></returns>  
    public DateTime GetWeekFirstDayMon(DateTime datetime)  
    {  
        //星期一为第一天  
        int weeknow = Convert.ToInt32(datetime.DayOfWeek);  
      
        //因为是以星期一为第一天,所以要判断weeknow等于0时,要向前推6天。  
        weeknow = (weeknow == 0 ? (7 - 1) : (weeknow - 1));  
        int daydiff = (-1) * weeknow;  
      
        //本周第一天  
        string FirstDay = datetime.AddDays(daydiff).ToString("yyyy-MM-dd");  
        return Convert.ToDateTime(FirstDay);  
    }  
      
    /// <summary>  
    /// 得到本周最后一天(以星期六为最后一天)  
    /// </summary>  
    /// <param name="datetime"></param>  
    /// <returns></returns>  
    public DateTime GetWeekLastDaySat(DateTime datetime)  
    {  
        //星期六为最后一天  
        int weeknow = Convert.ToInt32(datetime.DayOfWeek);  
        int daydiff = (7 - weeknow) - 1;  
      
        //本周最后一天  
        string LastDay = datetime.AddDays(daydiff).ToString("yyyy-MM-dd");  
        return Convert.ToDateTime(LastDay);  
    }  
      
    /// <summary>  
    /// 得到本周最后一天(以星期天为最后一天)  
    /// </summary>  
    /// <param name="datetime"></param>  
    /// <returns></returns>  
    public DateTime GetWeekLastDaySun(DateTime datetime)  
    {  
        //星期天为最后一天  
        int weeknow = Convert.ToInt32(datetime.DayOfWeek);  
        weeknow = (weeknow == 0 ? 7 : weeknow);  
        int daydiff = (7 - weeknow);  
      
        //本周最后一天  
        string LastDay = datetime.AddDays(daydiff).ToString("yyyy-MM-dd");  
        return Convert.ToDateTime(LastDay);  
    }  
    }  
    }  
  • 相关阅读:
    实现货币金额中文大写转换的程序
    大数阶乘的计算(三)
    全国15亿人口中选1000个代表有多少种选法?
    DB Query Analyzer 中断SQL语句的执行
    Android_Preference存取数据
    Centos 学习笔记软件包管理
    Centos学习笔记文件搜索命令
    《计算机时代》2011年第12期刊登出《DB Query Analyzer中断SQL语句的执行》
    Centos学习笔记linux用户管理
    Centos学习笔记 linux 常用命令:压缩解压命令
  • 原文地址:https://www.cnblogs.com/xuguanghui/p/7771986.html
Copyright © 2011-2022 走看看