c# - Automapper map from one object to nested objects

Question

What is the best way to map inner objects with Automapper 2.0

1. Use the solution in this question (Automapper 1.0)

2. Create a Custom Value Resolvers

3. ?

   public class DTOObject
   {
       // MainObject
       public int Id { get; set; }
       public string Name { get; set; }
   
       // SubObject (TopObject)
       public string TopText { get; set; }
       public string TopFont { get; set; }
   
       // SubObject (BottomObject)
       public string BottomText { get; set; }
       public string BottomFont { get; set; }
   }
   
   public class MainObject
   {
       public int Id { get; set; }
       public string Name { get; set; }
   
       public SubObject TopObject { get; set; }
       public SubObject BottomObject { get; set; }
   }
   
   public class SubObject
   {
       public string SubPropText { get; set; }
       public string SubPropFont { get; set; }
   }
   

Custom Value Resolvers

    public class CustomResolver : ValueResolver<DTOObject, SubObject>
    {
        protected override SubObject ResolveCore(DTOObject source)
        {
            return Mapper.Map<DTOObject, SubObject>(source);
        }
    }

Answer 1

对我来说，可以只使用 MapFrom （没有 ResolveUsing 让您有机会将此映射与 IQueryable 扩展一起使用）。因此，您将在 Automapper 配置中获得以下信息：

Mapper.CreateMap<DTOObject, SubObject>()
    .ForMember(dest => dest.SubPropText, opt => opt.MapFrom(x => x.BottomText))
    .ForMember(dest => dest.SubPropFont, opt => opt.MapFrom(x => x.BottomFont));

Mapper.CreateMap<DTOObject, MainObject>()
    .ForMember(dest => dest.SubPart, opt => opt.MapFrom(x => x));

Answer 2

I ended up creating my own value resolvers for any SubObjects of MainObject that come from DTOObject.

public class PartResolver<T> : ValueResolver<DTOObject, T>
{
    protected override T ResolveCore(DTOObject source)
    {
        return Mapper.Map<T>(source);
    }
}

Then in my Automapper config I create a map from the DTOObject to SubObject and use the ValueResolver to map that object into the MainObject

Mapper.CreateMap<DTOObject, SubObject>();

Mapper.CreateMap<DTOObject, MainObject>()
    .ForMember(dest => dest.SubPart, opt => opt.ResolveUsing<PartResolver<SubObject>>());

Answer 3

ResolveUsing不适用于最新版本的 AutoMapper。所以剩下的唯一选择是使用MapFrom。（使用@ZedRoth 解决方案）。