映射接口或抽象类组件 [英] Mapping interface or abstract class component

问题描述

请考虑以下简单用例：

pre $ $ $ $ $ $ $ $ $ $ $ $ Id {get;保护组}
public virtual IBar Bar {get;组; }
}

public interface IBar
{
string Text {get;组; }
}

public class Bar：IBar
{
public virtual string Text {get;组; }
}

以及流利的nhibernate地图类：

  public class FooMap：ClassMap< Foo> 
 {
 public FooMap（）
 {
 Id（x => x.Id）; 
 Component（x => x.Bar，m => 
 {
 m.Map（x => x.Text）; 
}）; 
 
 
 
 
 
 
当运行配置查询时，例外：
 $ b 
 
 
  NHibernate.InstantiationException ：
不能实例化抽象类或接口：NHMappingTest.IBar 
 
 NHibernate试图实例化一个 IBar 对象，而不是 Bar 具体类。如何让Fluent-NHibernate知道当属性返回一个接口或抽象基类时要实例化哪个具体类？
 
 $ b 
 编辑：明确指定通过编写 Component< Bar> （如Sly所建议的），组件的类型不起作用，并导致相同的异常。
 
 
 
  EDIT2：感谢vedklyv和Paul Batum：这样的映射应该很快 现在成为可能。 b $ b 
解决方案
我没有尝试过这个，但是我看到了一个流利的nh源代码，lambda被转换为具体的类：
  public class FooMap：ClassMap< Foo> 
 {
 public FooMap（）
 {
 Id（x => x.Id）; 
 Component（x =>（Bar）x.Bar，m => 
 {
 m.Map（x => x.Text）; 
}）; 
 
 
 
 
 
 
编辑：显然这与Sly的建议完全一样所以没有任何好处。我测试了它与流利nh的主干版本，它没有工作。如果你使用多对一的映射，它可以工作：
  public class FooMap：类映射<富> 
 {
 public FooMap（）
 {
 Id（x => x.Id）; 
参考< Bar>（x => x.Bar）.Cascade.All（）; 
} 
} 
 
公共类BarMap：ClassMap< Bar> 
 {
 public BarMap（）
 {
 Id（x => x.Id）; 
 Map（x => x.Text）; 
 
 
 
 
 
 更新 
 
 
 
这实际上是一个简单的修复。我已经提交了一个补丁（链接文本）使狡猾的解决方案工作。
 
Please consider the following simple use case:
public class Foo 
{ 
    public virtual int Id { get; protected set; } 
    public virtual IBar Bar { get; set; } 
} 

public interface IBar 
{ 
    string Text { get; set; } 
} 

public class Bar : IBar 
{ 
    public virtual string Text { get; set; } 
} 
And the fluent-nhibernate map class:
public class FooMap : ClassMap<Foo> 
{ 
    public FooMap() 
    { 
        Id(x => x.Id); 
        Component(x => x.Bar, m => 
        { 
            m.Map(x => x.Text); 
        }); 
    } 
} 
While running any query with configuration, I get the following exception: 

  
NHibernate.InstantiationException:
  "Cannot instantiate abstract class or interface: NHMappingTest.IBar"
It seems that NHibernate tries to instantiate an IBar object instead of the Bar concrete class. How to let Fluent-NHibernate know which concrete class to instantiate when the property returns an interface or an abstract base class?

EDIT: Explicitly specify the type of component by writing Component<Bar> (as suggested by Sly) has no effect and causes the same exception to occur.

EDIT2: Thanks to vedklyv and Paul Batum: such a mapping should be soon is now possible.
解决方案
I haven't tried this myself but i saw an example in the fluent nh source where the lambda is cast to the concrete class:
public class FooMap : ClassMap<Foo> 
{ 
    public FooMap() 
    { 
        Id(x => x.Id); 
        Component(x => (Bar) x.Bar, m => 
        { 
            m.Map(x => x.Text); 
        }); 
    } 
}
EDIT: Obviously that's exactly the same result as Sly's suggestion so that did no good. I tested it against the trunk version of fluent nh and it didn't work. It does work though if you use a many-to-one mapping:
  public class FooMap : ClassMap<Foo>
  {
    public FooMap()
    {
      Id(x => x.Id);
      References<Bar>(x => x.Bar).Cascade.All();
    }
  }

  public class BarMap : ClassMap<Bar>
  {
    public BarMap()
    {
      Id(x => x.Id);
      Map(x => x.Text);
    }
  }
UPDATE

This was actually an easy fix. I have submitted a patch (link text) that makes Sly's solution to work.

                        
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