NHibernate的查詢與<any>映射

Question

我使用NHibernate 3.2.0與微軟SQL Server 2005數據庫，C＃4.0和以下領域：

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> 

現在的我m試圖創建一個查詢，該查詢返回與名稱爲「Nightbar」的CocktailBar關聯的所有Foo對象。我如何創建這個查詢？在查詢中使用隱​​式多態（不管是HQL，Criteria還是QueryOver）都不包含在NHibernate Reference文檔中。

我試過如下：

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>(); 

，並得到了異常： 「System.InvalidOperationException：任何類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>();