Convert a string value to an entity in Automapper - viewmodel

Question

I am trying to figure out how to use Automapper when my entity has a field of type entity.
I've got 3 classes like these:
public abstract class Entity<IdK>
{
public virtual IdK Code { get; protected set; }
}
public class Contact : Entity
{
public virtual string Name { get; set; }
public virtual Company Company { get; set; }
}
public class Company : Entity
{
public virtual string Name { get; set; }
}
My class Contact contain an element of type Company.
I've also created a ViewModel to trasfer some infos to my view:
public ContactViewModel()
{
public Guid Code { get; set; }
public int Version { get; set; }
[DisplayName("Contact")]
public string Name { get; set; }
[DisplayName("Company")]
public string Company { get; set; }
}
In my viewmodel I've defined a field Company of type string. This is going to contain a value the user will chose from a dropdown (list of companies).
I've defined a bootstrapper when my App starts:
public class AutoMapperConfiguration
{
public static void Configure()
{
Mapper.Initialize(x => {
x.CreateMap<Domain.Contact, ViewModels.ContactViewModel>();
x.CreateMap<ViewModels.ContactViewModel, Domain.Contact>()
});
}
}
When I try to remap my ViewModel to my entity I get a conversion error (AutoMapper.AutoMapperMappingException).
Automapper can't figure out how to convert my Company (string) into an object of type Company, member of Contact.
Is it possible to define a rule so that Automapper know how to transform the string (company) into the code of my Company object, member of Contact?

Answer 1

You need to use a Resolver. Something like:
public class CompanyTypeResolver : ValueResolver<string, Company>
{
protected override Company ResolveCore(string name)
{
return new Company {Name = name};
}
}
Then in mapping code you call it like:
.ForMember(dto => dto.Company, opt => opt.ResolveUsing<CompanyTypeResolver>().FromMember(src => src.Name))