流畅的NHibernate AutoMapping与鉴别器

时间:2009-11-10 13:45:11

标签: nhibernate inheritance fluent-nhibernate nhibernate-mapping

我正在尝试使用鉴别器映射继承,但子类没有鉴别器值。如何使用AutoMappings解决它?

域对象如下:

public abstract class Item : GuidIdentityEntity {
   public virtual string Name { get; set; }
}

public class Product : Item {}
public class RawMaterial : Item {}

配置如下:

AssemblyOf<Item>()
    .IgnoreBase<GuidIdentityEntity>();
    .IncludeBase<Item>();
    .Setup(setup => {
        setup.DiscriminatorColumn = type => "Discriminator";
        setup.IsDiscriminated = type => type == typeof(Item);
        setup.SubclassStrategy = type => (type == typeof(Item)) 
            ? SubclassStrategy.Subclass 
            : SubclassStrategy.JoinedSubclass;
    });

映射的结果是:

<hibernate-mapping xmlns="urn:nhibernate-mapping-2.2" default-access="property" auto-import="true" default-cascade="none" default-lazy="true">
  <class xmlns="urn:nhibernate-mapping-2.2" name="Solution.Core.Products.Item, Solution.Core, Version=1.0.0.0, Culture=neutral, PublicKeyToken=2e5ef41be3839ad7" table="`Item`">
    <id name="Id" type="System.Guid, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089">
      <column name="Id" />
      <generator class="guid.comb" />
    </id>
    <discriminator type="String">
      <column name="Discriminator" />
    </discriminator>
    <property name="Name" type="System.String, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089">
      <column name="Name" />
    </property>
    <subclass name="Solution.Core.Products.RawMaterial, Solution.Core, Version=1.0.0.0, Culture=neutral, PublicKeyToken=2e5ef41be3839ad7" />
    <subclass name="Solution.Core.Products.Product, Solution.Core, Version=1.0.0.0, Culture=neutral, PublicKeyToken=2e5ef41be3839ad7" />
  </class>
</hibernate-mapping>

1 个答案:

答案 0 :(得分:7)

我发现这有效:

    public class SubclassConvention : ISubclassConvention, ISubclassConventionAcceptance
{
    #region IConvention<ISubclassInspector,ISubclassInstance> Members

    public void Apply(ISubclassInstance instance)
    {
        if (instance.Name == typeof(SalesInvoice).AssemblyQualifiedName)
            instance.DiscriminatorValue("SAL");
    }

    #endregion

    #region IConventionAcceptance<ISubclassInspector> Members

    public void Accept(IAcceptanceCriteria<ISubclassInspector> criteria)
    {
        criteria.Expect(subclass => Type.GetType(subclass.Name).BaseType == typeof(Invoice));
    }

    #endregion
}

在这种情况下,我有从Invoice类派生的SalesInvoice类。当前子类派生自Invoice时,子类的接受标准为true。鉴别器值是根据子类的类型分配的。 如您所见,我使用名称比较类型。遗憾的是由于某些原因,subclass.EntityType属性在运行时为null,因此我无法直接比较类型。