ReverseMap equivalent for CreateProjection

[jeffmccormick]

Version: 11.0.1

Question

With the new projection API, are there plans to include a ReverseMap() equivalent for IProjectionExpression<>? Or is the recommendation to simply create a separate map for the reverse direction.

The upgrade guide does not mention a path to follow for reverse mapping. It seems plausible that a IProjectionExpression<> could be reversed into an IMappingExpression<>.

Example

CreateProjection<Foo, Bar>()
    .ForMember(d => d.Name, opt => opt.MapFrom(src => src.Thing.Name))
    .ReverseMap() // Does not currently exist, would transition to IMappingExpression
    // The reverse map would perform the following line for us
    .ForPath(d => d.Thing.Name, opt => opt.MapFrom(src => src.Name));

[jbogard]

Nope I don't think so. I don't see why you'd project in two directions?

[jbogard]

Ahhh you want to project in one direction, map in the other, I see now.

[jbogard]

I'm not sure there's a technical reason why this wouldn't work - the interfaces share a common base class. We just have the interface to limit the configuration to what is possible for projections.

[lbargaoanu]

The only reason is to keep a clean API for CreateProjection, which is, after all, just a query. So a projection could support only the main use cases for a query. The rest can be done with CreateMap or the Advanced() extension method.

[jeffmccormick]

The projection is just a query, but I think this is a relatively common use case to want to map back to the entity. That being said, the clean API is an acceptable argument since it is easy enough to create a separate map. There may be some code duplication, but likely minimal in the common case. This can be marked as answered. Thanks!

[lbargaoanu]

If you must, see this. But I would simply create the map explicitly.