用linq在一行中获取max + min [英] Get max + min in one line with linq

问题描述

如何更改此方法，这样它也可以返回Max（t.StartTime）和Min（t.StartTime），只能在下面的一行中使用它？

How can I change this method so it also returns Max(t.StartTime) and Min(t.StartTime) with only using it in one line as below?

 public IQueryable<Timetable> GetTimetables()
    {
        return from t in _entities.Timetables
               select t;
    }

/ M

推荐答案

离开我的头顶（阅读：未经测试），并假定StartTime不可为空：

Off the top of my head (read: untested) and presuming StartTime is non-nullable:

public class TimetableWithMaxMin
{
    public Timetable Timetable { get; set; }
    public DateTime Max { get; set; }
    public DateTime Min { get; set; }
}

public IQueryable<TimetableWithMaxMin> GetTimetables()
{
    return from t in _entities.Timetables
           select new TimetableWithMaxMin
           {
               Timetable = t,
               Max = _entities.Timetables.Max(t => t.StartTime),
               Min = _entities.Timetables.Min(t => t.StartTime)
           };
}

当StartTime为空时，这会变得相当复杂。

This gets considerably more complicated when StartTime is nullable.

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