AutoMapper bidirectional mapping

Question

If I want to do bi-directional mapping, do I need to create two mapping?

Mapper.CreateMap<A, B>() and Mapper.CreateMap<B, A>()?

score 56 · Answer 1 · answered Oct 24 '10 at 18:44

56

Yes, but if you find yourself doing this often:

public static class AutoMapperExtensions
{
    public static void Bidirectional<TSource, TDestination>(this IMappingExpression<TSource, TDestination> expression)
    {
        Mapper.CreateMap<TDestination, TSource>();
    }
}

then:

Mapper.CreateMap<A, B>().Bidirectional();

answered Oct 24 '10 at 18:44

Eric Hauser

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while this may not answer the question, it certainly solves the underlying problem posed – hanzolo Feb 24 '15 at 19:12
Deprecated in 4.2, Removed in 5 :( https://stackoverflow.com/questions/38194012/automapper-mapper-does-not-contain-definition-for-createmap – Jim Elrod Jun 04 '17 at 02:11

score 28 · Answer 2 · answered Jan 30 '15 at 14:31

28

This is now baked into AutoMapper

Mapper.CreateMap<SourceType, DestType>().ReverseMap();

answered Jan 30 '15 at 14:31

ASG

957
9
20

1

This does not work with custom mappings, only when the property names are the same in both classes. – Michael Brown Feb 05 '16 at 21:35
@MichaelBrown even then, `ReverseMap` called on `IMappingExpression` returns an `IMappingExpression`, so the reverse custom mapping can then be defined. I move this be the new accepted answer. – Bondolin Feb 27 '20 at 17:48

score 21 · Accepted Answer · answered Mar 13 '10 at 16:21

21

Yes, because if you change the type of some property (for example DateTime -> string) it is not bidirectional (you will need to instruct Automapper how to convert string -> DateTime).

answered Mar 13 '10 at 16:21

Darin Dimitrov

1,023,142
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Makes sense, but it would be nice it the library TRIED to do the mapping as a convention, and you could explicitly disable it if it wasn't working. For example, I map domain objects to view models and bidirectional mapping would work perfectly for me. – John B Jan 17 '12 at 17:26

score 7 · Answer 4 · answered Jan 04 '13 at 08:40

Great idea Eric! I've added a return value, so the reverse mapping is configurable too.

public static class AutoMapperExtensions
{
    public static IMappingExpression<TDestination, TSource> Bidirectional<TSource, TDestination>(this IMappingExpression<TSource, TDestination> expression)
    {
        return Mapper.CreateMap<TDestination, TSource>();
    }
}

AutoMapper bidirectional mapping

4 Answers4

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