AutoMapper mapping int[] or List<int> from ViewModel to a List<Type> in Domain Model

Question

I'm new to AutoMapper and I've been reading and reading questions around here but I'm not quite able to figure out what looks like a very trivial question.

First my classes, then the question(s):

GatewayModel.cs

public class Gateway
{
    public int GatewayID { get; set; }
    public List<Category> Categories { get; set; }
    public ContentType ContentType { get; set; }

    // ...
}

public class Category
{
    public int ID { get; set; }
    public int Name { get; set; }

    public Category() { }
    public Category( int id ) { ID = id; }
    public Category( int id, string name ) { ID = id; Name = name; } 
}

public class ContentType
{
    public int ID { get; set; }
    public int Name { get; set; }

    public ContentType() { }
    public ContentType( int id ) { ID = id; }
    public ContentType( int id, string name ) { ID = id; Name = name; } 
}

GatewayViewModel.cs

public class GatewayViewModel
{
    public int GatewayID { get; set; }
    public int ContentTypeID { get; set; }
    public int[] CategoryID { get; set; }
    // or public List<int> CategoryID { get; set; }
    // ...
}

From what I've been reading all day this is what I have figured out so far. I don't know how to map the int[] (or List if it needs be) from the ViewModel to the List in the Model.

Global.asax.cs

Mapper.CreateMap<Gateway, GatewayViewModel>();
Mapper.CreateMap<GatewayViewModel, Gateway>()
    .ForMember( dest => dest.ContentType, opt => opt.MapFrom( src => new ContentType( src.ContentTypeID ) ) )
    .ForMember( /* NO IDEA ;) */ );

Basically I need to map all int[] CategoryID items from the ViewModel to the ID propery of the List Categories type in the Model. For the reverse mapping I need to map all ID's from the Category type to my int[] (or List) CategoryID but I think I have that figured out (haven't gotten there yet). If I need to do something similar for the reverse mapping, please let me know.

FYI, my int[] CategoryID in my ViewModel is bonded to a SelectList in my View.

I wish the CodePlex project site for AutoMapper had a more complete documentation but I'm happy they at least have what they have.

Thank you!

Answer 1

You could do the following:

Mapper
    .CreateMap<int, Category>()
    .ForMember(
        dest => dest.ID, 
        opt => opt.MapFrom(src => src)
);

Mapper
    .CreateMap<GatewayViewModel, Gateway>()
    .ForMember(
        dest => dest.Categories, 
        opt => opt.MapFrom(src => src.CategoryID)
);

var source = new GatewayViewModel
{
    CategoryID = new[] { 1, 2, 3 }
};

Gateway dst = Mapper.Map<GatewayViewModel, Gateway>(source);

Obviously you cannot map the Name property from the view model to the model because it is not present.