Question

我正在尝试制作一个自定义的 DateTime 对象集合，这些对象代表从当前日期时间到前进4周以及13周后的所有星期六。我试图通过最近关于集合顶部的当前日期时间来订购此集合。

TIA！

Answer 1

请尝试以下代码。

它会从当前日期的-13到+4周内迭代您需要的几周，并将特定日期调整为您需要的日期（在这种情况下为Saturday）

for (int i = -13; i <= 4; i++)
{
    var dateBackWithIWeeks = DateTime.Now.AddDays(i * 7);
    switch (dateBackWithIWeeks.DayOfWeek)
    {
        case DayOfWeek.Sunday:
            dateBackWithIWeeks = dateBackWithIWeeks.AddDays(-1);
            break;
        case DayOfWeek.Monday:
            dateBackWithIWeeks = dateBackWithIWeeks.AddDays(5);
            break;
        case DayOfWeek.Tuesday:
            dateBackWithIWeeks = dateBackWithIWeeks.AddDays(4);
            break;
        case DayOfWeek.Wednesday:
            dateBackWithIWeeks = dateBackWithIWeeks.AddDays(3);
            break;
        case DayOfWeek.Thursday:
            dateBackWithIWeeks = dateBackWithIWeeks.AddDays(2);
            break;
        case DayOfWeek.Friday:
            dateBackWithIWeeks = dateBackWithIWeeks.AddDays(1);
            break;
        case DayOfWeek.Saturday:
            break;
    }

    Console.WriteLine(dateBackWithIWeeks.Date);
}

Answer 2

根据评论更新

注意：代码可能需要调整，具体取决于您定义“13周前”（以及“从现在开始的4周”）的方式 - 您是在考虑日历周，还是13 * 7天？以下代码可以追溯到13 * 7天。

这是一种方法：

创建今天开始日期减去13周
将开始日期调整为下周六（如果不是星期六）
创建今天的结束日期加上4周
从开始到结束的每7天，将日期添加到列表中
按日期排序列表，降序

以下是一个示例实现：

var saturdays = new List<DateTime>();
var daysInWeek = 7;

var startDate = DateTime.Today.Subtract(TimeSpan.FromDays(13 * daysInWeek));

// Adjust start date so it is the first Saturday after 13 weeks before today
startDate = startDate.AddDays(DayOfWeek.Saturday - startDate.DayOfWeek);

var endDate = DateTime.Today.Add(TimeSpan.FromDays(4 * daysInWeek));

for (var curDate = startDate; curDate <= endDate; curDate = curDate.AddDays(daysInWeek))
{
    saturdays.Add(curDate);
}

// Order by date, descending
saturdays = saturdays.OrderByDescending(d => d).ToList();

// Output list of Saturdays to console for verification
saturdays.ForEach(s => Console.WriteLine(s.ToShortDateString()));

Answer 3

这个怎么样：

public static void Main()
{
    var start = DateTime.Now;
    var saturdays = GetSaturdays(start, 13, 4).OrderBy(d => Math.Abs((start - d).Days));
    foreach (var s in saturdays) 
    {
        Console.WriteLine(s.ToLongDateString());
    }
}

public static IEnumerable<DateTime> GetSaturdays(DateTime start, int weeksBack, int weeksForward)
{
    var startingSat = start.AddDays(6 - (int)start.DayOfWeek);
    for (int i = -weeksBack; i < weeksForward; i++)
    {
        yield return startingSat.AddDays(i * 7);
    }
}

您的问题仍然不清楚您希望如何订购，但您可以更改排序以反映您想要的任何内容。听起来你希望它们按照它们与开始日期的接近程度来排序，这几乎肯定是没有意义的。如果您只是希望它们按日期降序排序（如果您实际想要的话，那就是您应该说的那样）然后只需将OrderBy替换为：

.OrderByDescending(d => d);

这是fiddle

Answer 4

List<DateTime> saturdays = new List<DateTime>();
for (int i = -13; i < 4; i++)
    saturdays.Add(DateTime.Now.AddDays(i * 7 - (DateTime.Now.DayOfWeek - DayOfWeek.Saturday)));
DateTime today = DateTime.Now;
var more_recent = saturdays.OrderBy(day => Math.Abs(today.Subtract(day).Days)).ToList();

星期六DateTime提前4周，13周返回

4 个答案: