How to map to internal properties using Automapper?

Question

we've been using Automapper for sometime and we think it is great utility, thanks for creating it!

However, we have a question:

Question

"How do you configure AutoMapper to map a source property to an internal destination property?"

Background

In our layered architecture, Dto objects never leave the Data Access layer, only Domain objects are allowed to pass in and out of the Data Access layer. Thus, from a domain POV, domain objects shouldn't contain any database knowledge. However, in reality database Ids are very useful to carry around - expect the 'business-layer' developer shouldn't know about them.

Solution: add the database Ids to the domain object but market them as internal so that they aren't exposed to the 'business-layer'. Next expose the Common layer (which owns the domain objects) internals to the Data Access layer. Problem solved. Expect we can't figure out how to get Automapper (> v3.3.0) to work with our internal properties.

In, version 3.3.0 BindingFlags were exposed, which use to solve the problem.

Example

Common.Dll

public class Person
{
   public Parent Father { get; set; }
   internal int FatherId {get; private set; }
}

DataAccess.dll

internal class PersonDto
{
   public ParentDto Father { get; set; }
   public int FatherId {get; private set; }
}

In our Profile class we have CreateMap<PersonDto, Person>();

Edit 1 - Fixed a typo in the return type of Father.

Edit 2 - Added more info..

In the Common.Dll, we have Services something like this:

public class ParentService
{
    public Parent GetFather(Person person)
    {
        return repo.Parents.FirstOrDefault(parent => parent.Id = person.Father.Id);
    }
}

And in the Business.Dll we have developer's using the Services something like this:

var father = parentService.GetFather(son);
// use father separately or assign it to the son. Like so:
// son.Father = father;

The whole point is, we don't want the business developer's to have access to son.FatherId from the Businssess.Dll nor do they have access to the Dto object that created the domain object.

Thus, all the 'database' knowledge is encapsulated within in the various Common.dll Services or in the DataAccess.dll.

Thanks.

score 5 · Answer 1 · edited May 23 '17 at 12:24

This question is answered here.

I quote the answer for your convenience:

Just set the ShouldMapProperty property of your configuration object in the initialize method.

Here is an example using the static API, however, you should be able to achieve the same in a similar fashion by using the non-static API.

Mapper.Initialize(i =>
{
    i.ShouldMapProperty = p => p.GetMethod.IsPublic || p.GetMethod.IsAssembly;
    i.CreateMap<Source, Target>();                
});

How to map to internal properties using Automapper?

1 Answers1