检查日期时间是否与其他日期时间在同一周

Question

假设我在表格中有一个日期列表。现在我想查找与作为参数提供的日期在同一周内的所有行。

假设我有一张桌子：

• 2014-09-11
• 2014-09-12
• 2014-09-15

我给这个函数提供参数 2014-09-09，它必须从 monday->sunday 开始，并意识到 09-11 和 09-12 是一周的一部分，而不是 09-15。

究竟如何解决这个问题？

我考虑过检查年、月和周数，但你不能保证那个月是一样的......

那么你如何解决这样的问题呢？

Answer 1

DxCk 的评论是有效的。即使一年中的第一周或最后一周跨越两个不同的年份，此解决方案也可以工作：

检查两个日期的一周的第一天是否在同一天。 代码如下：

    private bool DatesAreInTheSameWeek(DateTime date1, DateTime date2)
    {
        var cal = System.Globalization.DateTimeFormatInfo.CurrentInfo.Calendar;
        var d1 = date1.Date.AddDays(-1 * (int)cal.GetDayOfWeek(date1));
        var d2 = date2.Date.AddDays(-1 * (int)cal.GetDayOfWeek(date2));

        return d1 == d2;
    }

Answer 2

检查 DateTime.Year 和 Calendar.GetWeekOfYear(DateTime, ...)。无需检查月份。

编辑：这是错误的，但我无法删除它。请参阅下面@Sparrow 的回答。

Answer 3

查找第一个日期所在周的开始日期和结束日期。然后检查第二个日期是否在这两者之间。

   public static bool DateInsideOneWeek(DateTime date1, DateTime date2)
    {
        DayOfWeek firstDayOfWeek = System.Globalization.CultureInfo.CurrentCulture.DateTimeFormat.FirstDayOfWeek;
        DateTime startDateOfWeek = date1.Date;
        while(startDateOfWeek.DayOfWeek != firstWeekDay)
        { startDateOfWeek = startDateOfWeek.AddDays(-1d); }
        DateTime endDateOfWeek = startDateOfWeek.AddDays(6d);
        return date2 >= startDateOfWeek && date2 <= endDateOfWeek;
    }

Answer 4

我的要求是找到本周下降的 DOB。希望这对您的疑问有所帮助。基本上这段代码背后的思想如下：

1. 将 DOB 更改为当年生日（例如：24-02-1988 改为 24-02-2018（当年）。
2. 如果生日周同时包含 dec 和 jan，则添加年份
3. 获取今天这一周的第一天。
4. 获取今天这一周的最后一天。

5. 检查当前年份的生日是否在今天一周的第一天和最后一天之间。

   private bool DatesAreInTheSameWeek(DateTime birthday)
   {
       if (birthday == DateTime.MinValue)
       {
           return false;
       }
       else
       {
           var birtdayWithCurrentYear = new DateTime(DateTime.Today.Year, birthday.Month, birthday.Day);
           if (birthday.Month == 1 && DateTime.Today.Month != 1)
           {
               birtdayWithCurrentYear = birtdayWithCurrentYear.AddYears(1);
           }
           DateTime firstDayInWeek = DateTime.Today.Date;
           while (firstDayInWeek.DayOfWeek != CultureInfo.CurrentCulture.DateTimeFormat.FirstDayOfWeek)
               firstDayInWeek = firstDayInWeek.AddDays(-1);var lastDayInWeek = firstDayInWeek.AddDays(7);
   
           return birtdayWithCurrentYear < lastDayInWeek && birtdayWithCurrentYear >= firstDayInWeek;
   
       }
   }
   

Answer 5

为什么不呢？

bool AreFallingInSameWeek(DateTime date1, DateTime date2)
{
    return date1.AddDays(-(int)date1.DayOfWeek) == date2.AddDays(-(int)date2.DayOfWeek);
}

如果您想使用星期日以外的任何一天作为一周的开始

bool AreFallingInSameWeek(DateTime date1, DateTime date2, DayOfWeek weekStartsOn)
{
    return date1.AddDays(-GetOffsetedDayofWeek(date1.DayOfWeek, (int)weekStartsOn)) == date2.AddDays(-GetOffsetedDayofWeek(date2.DayOfWeek, (int)weekStartsOn));
}

int GetOffsetedDayofWeek(DayOfWeek dayOfWeek, int offsetBy)
{
    return (((int)dayOfWeek - offsetBy + 7) % 7)
}

Answer 6

由于接受的答案包含评论中提到的@DxCK 错误，这是我的解决方案：

public static class DateExtensions
{
    private static void Swap<T>(ref T one, ref T two)
    {
        var temp = one;
        one = two;
        two = temp;
    }

    public static bool IsFromSameWeek(this DateTime first, DateTime second, DayOfWeek firstDayOfWeek = DayOfWeek.Monday)
    {
        // sort dates
        if (first > second)
        {
            Swap(ref first, ref second);
        }

        var daysDiff = (second - first).TotalDays;
        if (daysDiff >= 7)
        {
            return false;
        }

        const int TotalDaysInWeek = 7;
        var adjustedDayOfWeekFirst = (int)first.DayOfWeek + (first.DayOfWeek < firstDayOfWeek ? TotalDaysInWeek : 0);
        var adjustedDayOfWeekSecond = (int)second.DayOfWeek + (second.DayOfWeek < firstDayOfWeek ? TotalDaysInWeek : 0);

        return adjustedDayOfWeekSecond >= adjustedDayOfWeekFirst;
    }
}

这里还有link 的另一个正确解决方案，方法略有不同。

Answer 7

如果你不想使用 Calendar 类，你可以使用这个函数：

public static int WeekOfYear(DateTime dt)
{
    int startDays = 0;
    // first day of the year
    DateTime firstJanuary = new DateTime(dt.Year, 1, 1);

    if (firstJanuary.DayOfWeek == DayOfWeek.Tuesday)
    {
        startDays = 1;
    } 
    else if (firstJanuary.DayOfWeek == DayOfWeek.Wednesday)
    {
        startDays = 2;
    }
    else if (firstJanuary.DayOfWeek == DayOfWeek.Thursday)
    {
        startDays = 3;
    }
    else if (firstJanuary.DayOfWeek == DayOfWeek.Friday)
    {
        startDays = 4;
    }
    else if (firstJanuary.DayOfWeek == DayOfWeek.Saturday)
    {
        startDays = 5;
    }
    else if (firstJanuary.DayOfWeek == DayOfWeek.Sunday)
    {
        startDays = 6;
    }

    if (DateTimeFormatInfo.CurrentInfo.FirstDayOfWeek == DayOfWeek.Sunday)
    {
        startDays++;
        startDays = startDays % 7;
    }

    return ((dt.DayOfYear + startDays - 1) / 7) + 1;
}

Answer 8

使用：public virtual int GetWeekOfYear(DateTime time,CalendarWeekRule rule,DayOfWeek firstDayOfWeek) 的 Calendar 类