Question

I have the following Domain Object:

public class DomainClass
{
    public int Id { get; set; }

    public string A { get; set; }
    public string B { get; set; }
}

I have the following two objects that I want to map to:

public class Parent 
{
    public int Id { get; set; }
    public string A { get; set; }

    public Child Child { get; set; }
}

public class Child 
{
    public int Id { get; set; }
    public string B { get; set; }
}

I set up the following maps:

 Mapper.CreateMap<DomainClass, Parent>();
 Mapper.CreateMap<DomainClass, Child>();

If I map my object using the following call then the parent.Child property is null.

var domain = GetDomainObject();
var parent = Mapper.Map<DomainClass, Parent>(domain); // parent.Child is null

I know I can write the following:

var domain = GetDomainObject();
var parent = Mapper.Map<DomainClass, Parent>(domain);
parent.Child = Mapper.Map<DomainClass, Child>(domain);

Is there a way I can eliminate that second call and have AutoMapper do this for me?

Answer 1

You just need to specify that in the mapping:

Mapper.CreateMap<DomainClass, Child>();
Mapper.CreateMap<DomainClass, Parent>()
      .ForMember(d => d.Id, opt => opt.MapFrom(s => s.Id))
      .ForMember(d => d.A, opt => opt.MapFrom(s => s.A))
      .ForMember(d => d.Child, 
                 opt => opt.MapFrom(s => Mapper.Map<DomainClass, Child>(s)));

UPDATE:

For latest Automapper, see answer of @prostynick –

Just map the child using self. Tested with AutoMapper 6.1.1.

    CreateMap<DomainClass, Child>();
    CreateMap<DomainClass, Parent>()
        .ForMember(d => d.Child, opt => opt.MapFrom(s => s));