c# - 当输入为 IQueryable 时，无法让 Automapper 返回派生类型

Question

我可以让 Automapper 的 .Map 返回派生类型，但不能在 IQueryable 中返回。

数据结构:

public class Order { }
public class OnlineOrder : Order { }
public class MailOrder : Order { }

public class OrderDto { }
public class OnlineOrderDto : OrderDto { }
public class MailOrderDto : OrderDto { }

设置(~复制 from documentation ):

var mapperConfiguration = new MapperConfiguration(cfg =>
{
    cfg.CreateMap<Order, OrderDto>()
        .Include<OnlineOrder, OnlineOrderDto>()
        .Include<MailOrder, MailOrderDto>();
    cfg.CreateMap<OnlineOrder, OnlineOrderDto>();
    cfg.CreateMap<MailOrder, MailOrderDto>();
});

var order = new OnlineOrder();
var orders = new List<Order> { order }.AsQueryable();

var mapper = mapperConfiguration.CreateMapper().Map<OrderDto>(order); // is of type OnlineOrderDto, it works!

我尝试过的:

var projectTo = orders.ProjectTo<OrderDto>(mapperConfiguration); // is of type OrderDto, boo!
var useAsDataSource = orders.UseAsDataSource(mapperConfiguration).For<OrderDto>(); // is of type OrderDto, boo!

我看过documentation ，这个answer ，queryable extensions ，以及一些涉及 LINQ 的答案。我觉得我错过了一些明显的东西。

Answer 1

我认为这是不可能的。请参阅此已关闭的错误报告: https://github.com/AutoMapper/AutoMapper/issues/701