NHibernate的查询与<any>映射

Question

我使用NHibernate 3.2.0与微软SQL Server 2005数据库，C＃4.0和以下领域：

public class Foo 
{ 
    public virtual Guid Id { get; set; } 
    public virtual IBar MyBar { get; set; } 
} 
public interface IBar 
{ 
    Guid Id { get; set; } 
} 
public class CocktailBar : IBar 
{ 
    public virtual Guid Id { get; set; } 
    public virtual string Name { get; set; } 
} 
public class ProgressBar : IBar 
{ 
    public virtual Guid Id { get; set; } 
    public virtual int Progress { get; set; } 
} 

和映射

<hibernate-mapping> 
    <class name="Foo" table="FOO"> 
    <id name="Id"> 
     <generator class="guid.comb"/> 
    </id> 
    <any name="MyBar" meta-type="System.Guid" id-type="System.Guid"> 
     <meta-value class="MyNamespace.CocktailBar" value="716B5C04-4115-47BF-BE8A-A3B34D3607FC"/> 
     <meta-value class="MyNamespace.ProgressBar" value="65412938-C2DE-48FF-9E90-009881DBDD4F"/> 
     <column name="TypeOfBarId"/> 
     <column name="BarObjectId"/> 
    </any> 
    </class> 
</hibernate-mapping> 

现在的我m试图创建一个查询，该查询返回与名称为“Nightbar”的CocktailBar关联的所有Foo对象。我如何创建这个查询？在查询中使用隐​​式多态（不管是HQL，Criteria还是QueryOver）都不包含在NHibernate Reference文档中。

我试过如下：

Foo theFoo = session.QueryOver<Foo>() 
     .Where(c => c.MyBar.GetType().Name == "CocktailBar") 
     .JoinQueryOver<IBar>(c => c.MyBar) 
     .Where(c => ((CocktailBar)c).Name == "Nightbar") 
     .SingleOrDefault<Foo>(); 

，并得到了异常： “System.InvalidOperationException：任何类型不具有唯一留存引用” 在NHibernate.Type.AnyType.GetAssociatedEntityName

Answer 1

Foo theFoo = session.QueryOver<Foo>() 
    .Where(Restrictions.Eq("MyBar.class", typeOf(CocktailBar))) <-- here 
    .JoinQueryOver<IBar>(c => c.MyBar) 
    .Where(c => ((CocktailBar)c).Name == "Nightbar") 
    .SingleOrDefault<Foo>();