根据 asp.net mvc 5 的星期几指定当前星期答案

【问题标题】：specify current week based on day of week asp.net mvc 5根据 asp.net mvc 5 的星期几指定当前星期
【发布时间】：2016-03-08 09:05:56
【问题描述】：

目前，我正在尝试根据星期几进行查询，从该周的数据库中获取电影。所以一个电影周是从周四到下周三。当它是星期天，我只想要从星期天到星期三的电影。如果是周二，我只想要周二到周三的电影等。我真的很纠结在 asp 中你能做什么和不能做什么？

到目前为止，这是我的代码：

public IEnumerable<Viewing> GetUpcomingWeekViews()
    {
        var viewingList1 = _efdbContext.Viewing.ToList();

        DateTime currentDate = DateTime.Now.Date;
        var viewingList = _efdbContext.Viewing.ToList();

        DateTime startOfWeek = DateTime.Now.

        return viewingList.Where(v => (
            v.StartTime.Date == currentDate.Date) &&
            (v.StartTime.TimeOfDay > currentDate.TimeOfDay)
        ).OrderBy(v => v.StartTime);
    }

【问题讨论】：

您可以使用DateTime.DayOfWeek 属性进行计算

标签： asp.net asp.net-mvc

【解决方案1】：

使用DateTime 的DayOfWeek 属性：

var date = DateTime.Now;
var currentWeekday = (int)date.DayOfWeek;
const int wednesday = 3; // sunday is 0

var offset = 0; 
// if today is before wednesday, go to next wednesday
if (currentWeekday < wednesday) {
    offset = wednesday - currentWeekday;
}
// if today is wednesday, add a whole week till next wednesday
if(currentWeekday == wednesday) {
    offset = 7;
}
// if today is after wednesday, go to wednesday in a week
if(currentWeekday > wednesday) {
    offset = wednesday - currentWeekday + 7;
}

var nextWednesday = date.AddDays(offset);

Fiddle

【讨论】：

【解决方案2】：

首先使用DateOfWeek 计算从当前日期到所需日期的偏移量

public int CalculateOffset(DayOfWeek current, DayOfWeek desired) {
    // f( c, d ) = [7 - (c - d)] mod 7
    // f( c, d ) = [7 - c + d] mod 7
    // c is current day of week and 0 <= c < 7
    // d is desired day of the week and 0 <= d < 7
    int c = (int)current;
    int d = (int)desired;
    int offset = (7 - c + d) % 7;
    return offset == 0 ? 7 : offset;
}

并将该偏移量添加到当前DateTime 的Date

public IEnumerable<Viewing> GetUpcomingWeekViews(DayOfWeek desiredDayOfWeek = DayOfWeek.Thursday) {
    DateTime minStartTime = DateTime.Now;
    var currentDayOfWeek = minStartTime.DayOfWeek;

    int offset = CalculateOffset(currentDayOfWeek, desiredDayOfWeek);

    DateTime maxStartTime = minStartTime.Date.AddDays(offset);

    var viewingList = dbContext.Viewing.ToList();

    return viewingList
        .Where(v => minStartTime <= v.StartTime && v.StartTime < maxStartTime)
        .OrderBy(v => v.StartTime);
}

【讨论】：