如何使用NHibernate映射自定义列表

Question

I have a class with a custom list which inherits from List and cannot get the NHibernate mapping working.

public class MyClass
{
  private MyList<Foo> foos;

  public virtual MyList<Foo> Foos
  {
      get { return foos; }
      set { foos= value; }
  }
}

<bag name="Foos" access="property" cascade="all-delete-orphan" batch-size="5">
      <key column="MyClassId"/>
      <one-to-many class="Domain.Model.MyClass, Domain"/>
</bag>

I got the exception

Unable to cast object of type 'NHibernate.Collection.Generic.PersistentGenericBag 1[Domain.Model.Foo]' to type 'Domain.Model.MyList 1[Domain.Model.Foo]'.

Following this blog , I tried to wrap the bag in a component,

<component name="Foos" access="nosetter.camelcase-underscore">
  <bag name="Foos" access="property" cascade="all-delete-orphan" batch-size="5">
      <key column="MyClassId"/>
      <one-to-many class="Domain.Model.MyClass, Domain"/>
  </bag>
</component>

resulting in the error

Could not find a getter for property 'Foos' in class 'Domain.Model.MyList`1[Domain.Model.Foo]'

MyList has only a method to add objects.

public class MyList<T> : List<T>
{
    public new void Add(T item)
    {
        //custom stuff

        base.Add(item);
    }
}

Answer 1

If MyList<T> is a concrete type (and if I remember correctly) NHibernate will complain with an exception similar to (or same as?) the one your getting.

That could the be solved by using IList<T> instead.

Answer 2

This should work...

public class MyClass
{
    public virtual IList<Foo> Foos { get; private set; }

    public MyClass()
    {
        Foos = new MyList<Foo>();
    }
}

Changed the mapped property to an IList and set it to MyList