为什么没有DateTime.AddWeeks（），如何在52周前获取DateTime对象？ [英] Why is there no DateTime.AddWeeks(), and how can I get a DateTime object for 52 weeks ago?

问题描述

System.DateTime 对象具有用于 AddYears（），AddMonths（），AddDays（），AddSeconds（）等。

我注意到没有 AddWeeks（）。为什么？

I've noticed that there is no AddWeeks(). Why is this?

此外，我的要求是获取52周前的价格值。我知道这相当于1年，但具体时间约为52周。

Also, my requirement is to get a price value from 52 weeks ago. I know this equates to 1 year, but they were specific about 52 weeks.

我会做同样的事情吗？

yearOldPrice = _priceService.GetPriceForDate(price.Date.AddYears(-1));

as

yearOldPrice = _priceService.GetPriceForDate(price.Date.AddDays(-7 * 52));

我假设 .AddDays（-7 * 52）与 .AddWeeks（-52）相同，因为一周中有7天。

I ask on the presumption that .AddDays(-7 * 52) is the same as .AddWeeks(-52), 'cause there's 7 days in a week.

推荐答案

正如您在问题中所指出的，与年和月不同，每周总是有整整7天（无论如何，在我的日历上），因此几乎没有当您需要做的是.AddDays（weeks * 7）时，可以通过使用AddWeeks方法获得。虽然您必须质疑当它们具有AddMinutes和AddHours时的逻辑！

As you've noted in your question, unlike Years and Months, there are always exactly 7 days per week (on my calendar, anyway), so there's very little to be gained by having an AddWeeks method when all you need to do is .AddDays(weeks * 7). Though you have to question the logic when they have AddMinutes and AddHours! Damn them and their inconsistencies!

如果确实困扰您，您总是可以为.AddWeeks创建扩展方法，但是：

You could always create an extension method for .AddWeeks if it really bothers you, though:

public static class DateTimeExtensions
{
    public static DateTime AddWeeks(this DateTime dateTime, int numberOfWeeks)
    {
        return dateTime.AddDays(numberOfWeeks * 7);
    }
}

正如其他人指出的那样，一年不是52周。

And as others have pointed out, a year is not 52 weeks.

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