AutoMapper，将一种类型映射到两种不同的类型

Question

我有以下型号：

public class Stuff
{
    ...
    public IList<Place> Places { get; set; } = null!;
    ...
}

public class Place
{
    ...
    public IList<Stuff> Stuffs { get; set; } = null!;
    ...
}

public class StuffEntity 
{
    ...
    public IList<PlaceStuffEntity> Places { get; set; } = null!;
    ...
}

public class PlaceEntity 
{
    ...
    public IList<PlaceStuffEntity> Stuffs { get; set; } = null!;
    ...
}

public class PlaceStuffEntity
{
    public int StuffId { get; private set; }
    public StuffEntity Stuff { get; set; } = null!;
    public int PlaceId { get; private set; }
    public PlaceEntity Place { get; set; } = null!;
}

cfg.CreateMap<StuffEntity, Stuff>()
   .ForMember(d => d.Places,
              opt => opt.MapFrom(s => s.Places.Select(y => y.Place).ToList()));
cfg.CreateMap<PlaceEntity, Place>()
   .ForMember(d => d.Stuffs,
              opt => opt.MapFrom(s => s.Places.Select(y => y.Stuff).ToList()));
cfg.CreateMap<PlaceAndStuffEntity, Stuff>()              // < -- Issue
   .IncludeMembers(entity=> entity.Stuff);
cfg.CreateMap<PlaceAndStuffEntity, Place>()              // < -- Issue
   .IncludeMembers(entity=> entity.Place);

由于某种原因，当我添加最后两行时，转换不起作用......

但是，如果我只添加一行，例如用于转换PlaceAndStuffEntity -> Stuff仅适用于PlaceEntity -> Place一种转换

var place = mapper.Map<Place>(placeEntity); // <- This works
var stuff = mapper.Map<Stuff>(stuffEntity); // <- Does not work !!

有没有办法正确处理以下转换？

Answer 1

听起来您想通过连接表 (PlaceAndStuff) 映射到其他实体类型。 例如，在您的 Place 中获取 Stuff 列表，Stuff 中获取 Place 列表，您希望指示 Automapper 如何在连接表中导航。

例如：

cfg.CreateMap<StuffEntity, Stuff>()             
   .ForMember(x => x.Places, opt => opt.MapFrom(src => src.PlaceEntity));
// Where StuffEntity.Places = PlaceAndStuffEntities, to map Stuff.Places use PlaceAndStuffs.PlaceEntity

cfg.CreateMap<PlaceEntity, Place>()             
   .ForMember(x => x.Stuffs, opt => opt.MapFrom(src => src.StuffEntity));

因此，与其试图告诉 EF 如何映射连接实体 PlaceStuffEntity，我们专注于 PlaceEntity 和 StuffEntity，并告诉 Automapper 导航连接实体以通过连接实体获取实际的 Stuff 和 Place 亲属。

Answer 2

改变

cfg.CreateMap<PlaceEntity, Place>()
   .ForMember(d => d.Stuffs,
              opt => opt.MapFrom(s => s.Places.Select(y => y.Stuff).ToList()));

到

cfg.CreateMap<PlaceEntity, Place>()
   .ForMember(d => d.Stuffs,
              opt => opt.MapFrom(s => s.Stuffs.Select(y => y.Stuff).ToList()));

源类型 PlaceEntity 没有名为 Places 的属性，只有 Stuffs。