c# - 创建一个 LINQ 查询，其中将包括本周除今天和昨天之外的所有条目

Question

我正在使用 LINQ 查询来检索本周的所有记录，但是，我需要排除今天和昨天的所有记录。

这是我目前所拥有的:

DateTime startThisWeek = DateFunctions.GetFirstDayOfWeek(DateTime.Now).AddDays(1);
DateTime endOfThisWeek = startThisWeek.AddDays(6);
DateTime today = DateTime.Now;
DateTime yesterday = DateTime.Now.AddDays(-1);

var notificationList = 
    (from n in db.DashboardNotifications
                 .OrderByDescending(n => n.NotificationDateTime)
     where (n.NotificationDateTime >= startThisWeek && 
            n.NotificationDateTime <= endOfThisWeek) &&  
           (n.NotificationDateTime != today && 
            n.NotificationDateTime != yesterday)
     select n).ToList();

上述查询的问题是它没有返回正确的记录，它也显示了今天的记录。

Answer 1

假设您的 DateFunctions.GetFirstDayOfWeek 工作正常

DateTime startThisWeek = DateFunctions.GetFirstDayOfWeek(DateTime.Now);
DateTime yesterday  = DateTime.Today.AddDays(-1);

var notificationList = 
   (from n in db.DashboardNotifications
    where n.NotificationDateTime.Date >= startThisWeek.Date && 
          n.NotificationDateTime.Date < yesterday)
    orderby n.NotificationDateTime descending
    select n).ToList();

注释:如果本周的开始时间不在昨天之前，那么您将不会得到任何记录。否则昨天总是在本周末之前。

如何正确获取星期几:

public static class DateTimeExtensions
{
    public static DateTime StartOfWeek(this DateTime date, 
        DayOfWeek startOfWeek = DayOfWeek.Monday)
    {
        DateTime result = date;

        while (result.DayOfWeek != startOfWeek)
            result = date.AddDays(-1);

        return result.Date;
    }
}