I have one main interface that other interfaces inherit from. I would like the main automapper map to switch and return another relevant defined mapping depending on the object type.

For example, call the main interface IGroup:

public interface IGroup {...}

And then make some more interfaces that inherit from that:

public interface IFamily : IGroup {...}
public interface IFriends : IGroup {...}
public interface INeighbours : IGroup {...}

I define relevant mappings for each inherited group:

CreateMap<IFamily, GroupListView>() ...etc

On the main IGroup map, I would like to switch so that if I have a collection of IGroup it returns the relevant mapping for each item.

I have tried

            CreateMap<IGroup, GroupListView>()
            .Include<IFamily, GroupListView>()
            .Include<IFriends, GroupListView>()
            .Include<INeighbours, GroupListView>()
            .ConstructUsing((IGroup group, ResolutionContext context) =>
            {
                switch (group)
                {
                    case IFamily family:
                        return context.Mapper.Map<IFamily, GroupListView>(family);

                    case IFriends friends:
                        return context.Mapper.Map<IFriends, GroupListView>(friends);

                    case INeighbours neighbors:
                        return context.Mapper.Map<INeighbours, GroupListView>(neighbors);

                    default:
                        throw new InvalidOperationException("Unknown group type: " + group.GetType().FullName);
                }
            })

But validation complains that there are unmapped members on the IGroup interface because I’m not actually defining anything.

If I define anything after or opt.Ignore, then it overrides the ConstructUsing result.

What would be even better is if instead of throwing an error on unrecognised IGroup type, it returned a default map for IGroup.

Many thanks.