Automapper : mapping issue with inheritance and abstract base class on collections with Entity Framework 4 Proxy Pocos

This answer comes ‘a bit’ late as I’ve just faced the same issue with EF4 POCO proxies.

I solved it using a custom converter that calls Mapper.DynamicMap<TDestination>(object source) to invoke the runtime type conversion, rather than the .Include<TOtherSource, TOtherDestinatio>().

It works fine for me.

In your case you would define the following converter:

class PaymentConverter : ITypeConverter<Payment, DtoPayment> {
    public DtoPayment Convert( ResolutionContext context ) {
        return Mapper.DynamicMap<DtoPayment>( context.SourceValue );
    }
}

And then:

Mapper.CreateMap<Payment, DtoPayment>().ConvertUsing<PaymentConverter>();
Mapper.CreateMap<CashPayment, DtoCashPayment>();
Mapper.CreateMap<CreditCardPayment, DtoCreditCardPayment>();