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I'm trying to create a mapping between a LLBLGen Entity and a DTO using AutoMapper.

My DTO's looks as followed:

// Parent
public int Id { get; set; }
public List<Child> Children{ get; set; } // One to Many

// Child
public int Id { get; set; }
public int Parent { get; set; } // Foreign key to parent Id

The ParentEntity contains a ChildCollection with the same name as the DTO List and an Id (with other LLBL fields that need to be ignored). So when the ParentEntity gets mapped to the Parent DTO it should also map the ChildCollection to a List of Children.

This is what I got so far:

ParentEntity parentEntity = new ParentEntity(id);

AutoMapper.Mapper.CreateMap<ParentEntity, Parent>();
AutoMapper.Mapper.CreateMap<ChildCollection, List<Child>>();

var parent = AutoMapper.Mapper.Map<Parent>(parentEntity);

This results in the Id getting mapped but List has count 0.

How can I make it work?

UPDATE:

Tried the same as my previous attempt but manually mapping the List of Children also results in the same problem: Id gets mapped but List is empty.

Mapper.CreateMap<ParentEntity, Parent>()
    .ForMember(dto => dto.Children, opt => opt.MapFrom(m => m.Children));
Sam
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  • Please show `ChildCollection` class. What is the type of its `List` property? I think it is better to provide full relevant source code of your entities and DTOs to resolve why mapping is not working. – Ilya Chumakov Dec 30 '15 at 12:58
  • The DTOs are already shown in my question. The ChildCollection contains ChildEntities which contain the same fields as the DTO and a lot more LLBL related resources. Pasting the full resources of these collection/entities will not be useful and too much. If you worked with LLBL before than you should have an idea of what these classes contain. – Sam Dec 30 '15 at 13:14

1 Answers1

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This line is not helpful:

AutoMapper.Mapper.CreateMap<ChildCollection, List<Child>>();

Instead of this, you should to add explicit map class-to-class:

AutoMapper.Mapper.CreateMap<ChildEntity, Child>();

And then you should specify exact properties to map. Both properties should have List type or similar (List<ChildEntity> as source and List<Child> as destination). So, if ParentEntity and Parent classes both have Children property, you even does not have to specify:

.ForMember(dto => dto.Children, opt => opt.MapFrom(m => m.Children));

default mapping in enough:

  Mapper.CreateMap<ParentEntity, Parent>();
Ilya Chumakov
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  • You found it! The solution was that the ChildEntity and Child DTO needed a explicit class-to-class map. I assumed the problem was more complex and had something to do with the List types not being similar like you mentioned because LLBL has a custom List implementation (EntityCollections). Thanks! – Sam Dec 30 '15 at 14:36