FluentNHibernate, getting 1 column from another table - nhibernate

Question

We're using FluentNHibernate and we have run into a problem where our object model requires data from two tables like so:
public class MyModel
{
public virtual int Id { get; set; }
public virtual string Name { get; set; }
public virtual int FooId { get; set; }
public virtual string FooName { get; set; }
}
Where there is a MyModel table that has Id, Name, and FooId as a foreign key into the Foo table. The Foo tables contains Id and FooName.
This problem is very similar to another post here: Nhibernate: join tables and get single column from other table but I am trying to figure out how to do it with FluentNHibernate.
I can make the Id, Name, and FooId very easily..but mapping FooName I am having trouble with. This is my class map:
public class MyModelClassMap : ClassMap<MyModel>
{
public MyModelClassMap()
{
this.Id(a => a.Id).Column("AccountId").GeneratedBy.Identity();
this.Map(a => a.Name);
this.Map(a => a.FooId);
// my attempt to map FooName but it doesn't work
this.Join("Foo", join => join.KeyColumn("FooId").Map(a => a.FooName));
}
}
with that mapping I get this error:
The element 'class' in namespace 'urn:nhibernate-mapping-2.2' has invalid child element 'join' in namespace 'urn:nhibernate-mapping-2.2'. List of possible elements expected: 'joined-subclass, loader, sql-insert, sql-update, sql-delete, filter, resultset, query, sql-query' in namespace 'urn:nhibernate-mapping-2.2'.
any ideas?

Answer 1

I think you misunderstood something here.
Instead of having Id, Name, FooId and FooName in same class you need to create two classes
public class MyModel
{
public virtual int Id { get; set; }
public virtual string Name { get; set; }
public virtual Foo Foo { get; set; }
}
public class Foo
{
public virtual int Id { get; set; }
public virtual string FooName { get; set; }
}
And your mapping classes for these:
public class MyModelMapping : ClassMap<MyModel>
{
public MyModelMapping()
{
this.Id(x => x.Id);
this.Map(x => x.Name);
this.References(x => x.Foo);
}
}
public class FooMapping : ClassMap<Foo>
{
public FooMapping()
{
this.Id(x => x.Id);
this.Map(x => x.FooName);
}
}
this should help.
But remember Convention other Configuration :)