有没有更好的方法来设置linq中项目列表的公共属性

Question

我有以下课程:

public class Vehicle
{
    public string Make { get; set; }
    public DateTime DateManufactured { get; set; }
}

然后,我列出了一些车辆:

        var dateTime1 = DateTime.Now.AddDays(-7);
        var dateTime2 = DateTime.Now.AddDays(-8);
        var dateTime3 = DateTime.Now.AddDays(-9);

        var vehicles = new List<Vehicle>
            {
                new Vehicle {Make = "Ferrari", DateManufactured = dateTime1},
                new Vehicle {Make = "Mazda", DateManufactured = dateTime2},
                new Vehicle {Make = "Dodge", DateManufactured = dateTime3},
                new Vehicle {Make = "Holden", DateManufactured = dateTime1},
                new Vehicle {Make = "Chrysler", DateManufactured = dateTime2},
                new Vehicle {Make = "Mazda", DateManufactured = dateTime3},
            };

接下来,我试图获得DatesManufactured列表以及每个日期在该日期制造的车辆.

所以我去了:

var vehiclesGroupedByDate = vechicles.GroupBy(x => x.DateManufactured)
                .Select(x => new
                    {
                        x.First().DateManufactured,
                        Vehicles = x.ToList()
                    });

这会罚款,但我不确定这x.First()部分.它有效,但感觉不太对劲.有人知道更优雅的编码方式吗？

Answer 1

当您使用时GroupBy,它将创建一个IGrouping<TKey, TItem>,因此您可以简单地执行以下操作:

var vehiclesGroupedByDate = vechicles.GroupBy(x => x.DateManufactured)
            .Select(x => new
                {
                    x.Key,
                    Vehicles = x.ToList()
                });