Mapping interface or abstract class component
- by Yann Trevin
Please consider the following simple use case:
public class Foo
{
public virtual int Id
{
get;
protected set;
}
public virtual IBar Bar
{
get;
set;
}
}
public interface IBar
{
string Text
{
get;
set;
}
}
public class Bar : IBar
{
public virtual string Text
{
get;
set;
}
}
And the fluent-nhibernate map class:
public class FooMap : ClassMap<Foo>
{
public FooMap()
{
Id(x => x.Id);
Component(x => x.Bar, m =>
{
m.Map(x => x.Text);
});
}
}
While running any query with configuration, I get the following exception:
NHibernate.InstantiationException:
"Cannot instantiate abstract class or interface: NHMappingTest.IBar"
It seems that NHibernate tries to instantiate an IBar object instead of the Bar concrete class. How to let Fluent-NHibernate know which concrete class to instantiate when the property returns an interface or an abstract base class?
EDIT: Explicitly specify the type of component by writing Component<Bar> (as suggested by Sly) has no effect and causes the same exception to occur.
EDIT2: Thanks to vedklyv and Paul Batum: such a mapping should be soon is now possible.
