如何获得基于年周数的月周数(即第33周) [英] How could I get months week number based on year week number (i.e week 33)

问题描述

我想知道如何根据一年中星期几的序数来计算一周中的星期几.例如，我要处理第33周，我应该知道8月是第2周. 我已经计算了数月，但现在我要处理数周.

I'm wondering how can I calculate what is the week of the month based on the ordinal number of the week of the year. For example I'm dealing with week 33, I should know that's Week 2 in august. I allready calculated months but now I'm dealing with weeks.

我已经有解决方案了，但是对我来说似乎很肮脏.

I allready have a solution, but it seems dirty to me..

代码如下:

var data = query.GroupBy(x => CultureInfo.CurrentCulture.Calendar.GetWeekOfYear(x.CreatedDate ?? DateTime.UtcNow, CalendarWeekRule.FirstDay, DayOfWeek.Monday))
.Select(article => new ArticleSimpleObject
{
    Week = GetWeekNumberOfMonth(article.FirstOrDefault().CreatedDate.Value),
    Amount = article.Sum(x => x.Amount),
    Month = article.FirstOrDefault().CreatedDate.Value.Month
});

这是我用来获取周数的方法:

And here's the method which I used to get week numbers:

 private static int GetWeekNumberOfMonth(DateTime date)
 {
      date = date.Date;
      DateTime firstMonthDay = new DateTime(date.Year, date.Month, 1);
      DateTime firstMonthMonday = firstMonthDay.AddDays((DayOfWeek.Monday + 7 - firstMonthDay.DayOfWeek) % 7);
      if (firstMonthMonday > date)
      {
          firstMonthDay = firstMonthDay.AddMonths(-1);
          firstMonthMonday = firstMonthDay.AddDays((DayOfWeek.Monday + 7 - firstMonthDay.DayOfWeek) % 7);
       }
      return (date - firstMonthMonday).Days / 7 + 1;
  }

在我写给大家的时候，这种解决方案有效，

As I wrote guys, this solutions works,

但是我个人不喜欢它，我想还有一个更优雅的解决方案，这就是为什么如果有经验的人帮助我们解决这个问题，我会发布此问题以帮助自己和将来的读者:)

but I personally don't like it, I guess there is more elegant solution, and that's why I posted this question to help to myself and to future readers if some experienced person helps us to solve this :)

也许可以基于Calendar类 https://docs.microsoft.com/zh-cn/dotnet/api/system.globalization.calendar?view=netframework-4.8

Maybe this could be solved based on Calendar class https://docs.microsoft.com/en-us/dotnet/api/system.globalization.calendar?view=netframework-4.8

我已经尝试了一些变体，但是我什至没有解决它..

I've tried some variant but I was not even close to solve it..

谢谢大家

欢呼

推荐答案

您可以编写一些通用扩展来对此进行简单计算.

You can write a couple of general extensions to compute this a little bit simpler.

首先，您需要从一周中的特定日期开始的一周的第一个日期作为日期:

First, you need the first date of the week starting on a particular day of week for a date:

public static DateTime FirstDateOfWeekStarting(this DateTime aDate, DayOfWeek dow) => aDate.Date.AddDays((int)dow - (int)aDate.DayOfWeek);

然后，您可以轻松地将第一个日期的月份中的日期转换为月份中的周号:

Then, you can easily convert the day of month of that first date to the Week Number in the month:

public static int WeekStartingDOWNumOfMonth(this DateTime aDate, DayOfWeek dow) => (aDate.FirstDateOfWeekStarting(dow).Day-1) / 7 + 1;

对于您从星期一开始的几周的特定情况，

And, for your specific case of weeks beginning with Monday,

public static int WeekStartingMonNumOfMonth(this DateTime aDate) => aDate.WeekStartingDOWNumOfMonth(DayOfWeek.Monday);

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