Fluent NHibernate inheritance mapping problem

问题:

I am using Fluent NHibernate with table per subclass inheritance mapping. I want to reference to a list of specific objects, but i can't figure out, how to restict the result to objects of one specific class.

class PetMap : ClassMap<Pet> {     public PetMap()     {         Id(c => c.ID).GeneratedBy.Identity();                 } }  class DogMap : ClassMap<Dog> {     public DogMap()     {        Mac(c => c.DogSpecificProperty);                                     } }  class CatMap : SubclassMap<Cat> {     public CatMap()     {        Mac(c => c.CatSpecificProperty);                                         } }  class PersonMap : ClassMap<Person> {     public PersonMap()     {           Id(c => c.ID).GeneratedBy.Identity();          //this works fine         HasMany(c => c.Pets);          //this dosen't work, because the result contains dogs and cats         //how can I tell NHibernate to only fetch dogs or cats?         HasMany<Pet>(c => c.Cats);         HasMany<Pet>(c => c.Dogs);     } }  class Pet {     int ID; } class Dog : Pet {    object DogSpecificProperty; } class Cat : Pet {    object CatSpecificProperty; } class Person {    int ID;    IList<Pet> Pets;    IList<Dog> Dogs;    IList<Cat> Cats; } 

Can anyone help me? Please excuse my poor english.

回答1:

I'm not an expert in Fluent NH, but it seems to me that your person map should look like this:

class PersonMap : ClassMap<Person> {     public PersonMap()     {           Id(c => c.ID).GeneratedBy.Identity();          //this works fine         HasMany(c => c.Pets);          //this dosen't work, because the result contains dogs and cats         //how can I tell NHibernate to only fetch dogs or cats?         HasMany<Cat>(c => c.Cats);         HasMany<Dog>(c => c.Dogs);     } } 

Because you're Person has a Dogs property which is an IList not IList, and conversely the same for Cats.

文章来源: Fluent NHibernate inheritance mapping problem