是否可以使用自动映射器对资源中的数据进行分组？

Question

是否可以使用自动映射器对资源中的数据进行分组？

例如：

public class Order
{
    public Guid ID{ get; set; }

    public ICollection<OrderLine> OrderLines { get; set; }
}

public class OrderLine
{

    public Guid OrderID { get; set; }
    public Order Order { get; set; }
    public Guid ProductID { get; set; }
    public Product Product { get; set; }
    public int Year { get; set }
}

public class Product
{

    public Guid ID{ get; set; }

    public ICollection<OrderLine> OrderLines { get; set; }
}

 public class OrderResource
    {
        public Guid ID { get; set; }

        public ICollection<YearResource> Years { get; set; }

        public OrderResource()
        {
            Years = new Collection<YearResource>();
        }
    }

public class YearResource
{
    public int Year { get; set; }
    public ICollection<Guid> ProductIds { get; set; }
}

例如，我希望基于年份对productId进行分组：

{
    id: "random-id-tst",
    years: [
        {
            year: 1,
            productIds: ['guid-id-1', 'guid-id-2'],
        },
    ]
}

我正在努力使其与Years分组。所以现在我明白了：

{
    id: "random-id-tst",
    years: [
        {
            year: 1,
            productIds: ['guid-id-1'],
        },
        {
            year: 1,
            productIds: ['guid-id-2'],
        },
    ]
}

我尝试使用groupBy，但我认为automapper不支持它，并且无法使其正常工作。

cfg.CreateMap<Order, OrderResource>().ForMember(dest => dest.Years, opt => opt.MapFrom(src => src.OrderLines.Select(ol => ol.Product).ToList()))

// tried grouping on OrderLines but that's not working
cfg.CreateMap<Product, YearResource>().ForMember(dest => dest.Year, opt => opt.MapFrom(src => src.OrderLines.Select(e => e.Year).First()));

Answer 1

您需要使用LINQ的GroupBy。这是有关GroupBy用法的示例，此示例提供了根据Cars的名称对它们进行分组的方法，

List<Car> cars = new List<Car>();
cars.Add(new Car() { Name = "Renault", Price = 250 });
cars.Add(new Car() { Name = "BMW", Price = 700 });
cars.Add(new Car() { Name = "Renault", Price = 150 });
cars.Add(new Car() { Name = "Renault", Price = 250 });
cars.Add(new Car() { Name = "Renault", Price = 100 });

List<Car> result = cars.GroupBy(x => x.Name).Select(x => new Car() { Name = x.Key, Price = x.Sum(y=>y.Price) }).ToList();

//to print output
result.ForEach(x => Console.WriteLine(string.Concat("Name: ", x.Name, " Total Price: ", x.Price)));
Console.ReadKey();

和汽车模型，

public class Car {
    public string Name { get; set; }
    public int Price { get; set; }
}