How do you map an entity -> interface relationship using Fluent NHibernate?

Question

given the following class definition:

public class Order {
  public IProduct Product {get;set;}
}

I have this (fluent) mapping

References(x=>x.Product, "ProductId");

And get this exception: An association from the table Orders refers to an unmapped class, which makes sense because it doesn't know what implementation I will pass to it.

I understand why I have to define the type in the mapping (IProduct could be anything) but I'm not sure how to do it.

Thanks,

Kyle

Answer 1

I think what you're looking for is .References<Product>(x=>x.Product, "ProductId");

Incidentally the same is true for .HasMany<>

This seems to do the same as <... class="Product" /> in xml

I wouldn't recommend mapping to the interface as it breaks the whole point of using one - you run into problems as soon as it starts implementing IStorable and NH can't cope with the multiple inheritance.

Answer 2

Try mapping the interface IProduct instead of the concrete class Product. (Note, I'm not talking about mapping the Product field of class Order.)