NHibernate:获取所引用抽象实体的具体类型 [英] NHibernate: Get concrete type of referenced abstract entity

问题描述

我有以下课程:

public abstract class FooBase 
{
     public virtual Guid Id { get; set; }
}

public class FooTypeA : FooBase
{
     public virtual string TypeAStuff { get; set; }
}

public class Bar
{
     public virtual Guid Id { get; set; }
     public virtual FooBase Foo { get; }
}

FooBase和FooTypeA使用每类表层次结构模式进行映射. 条形图是这样映射的:

FooBase and FooTypeA are mapped using the table-per-class-heirarchy pattern. Bar is mapped like this:

public class BarDbMap : ClassMap<Bar>
{
     public BarDbMap()
     {
          Id(x => x.Id);
          References(x => x.Foo)
               .LazyLoad();
     }
}

因此，当我加载Bar时，其Foo属性只是一个代理.

So when I load a Bar, its Foo property is only a proxy.

如何获取Foo的子类类型(即FooTypeA)?

How do I get the subclass type of Foo (i.e. FooTypeA)?

我已经阅读了很多NH文档和论坛帖子.他们描述了获取父类型而不是子类的工作方式.

I have read through a lot of NH docs and forum posts. They describe ways of getting that work for getting the parent type, but not the subclass.

如果我尝试取消代理，则会收到类似以下错误: object是FooBase的未初始化代理

If I try to unproxy the class, I receive errors like: object was an uninitialized proxy for FooBase

推荐答案

我研究出如何避免收到的异常.这是取消代理FooBase的方法:

I worked out how to avoid the exception I was receiving. Here is a method that unproxies FooBase:

    public static T Unproxy<T>(this T obj, ISession session)
    {
        if (!NHibernateUtil.IsInitialized(obj))
        {
            NHibernateUtil.Initialize(obj);
        }

        if (obj is INHibernateProxy)
        {    
            return (T) session.GetSessionImplementation().PersistenceContext.Unproxy(obj);
        }
        return obj;
    }

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