EF核心流利的映射到内对象属性

问题描述

我有一个包含一些属性的类。
对于一些建筑方面的原因，我有另外一个客体的实例到我的课。

I have a class that contains some properties.For some architectural reasons, I have an instance of another objet into my class.

简单的例子

public class MyEntity {
   public MySubEntity SubEntity {get; set;}
}

对于这一点，我创建这样一口流利的映射：

For this, I create fluent mapping like :

builder.ToTable(MyEntity.CONST_TABLE_NAME);
builder.HasKey(m => m.Id);
builder.Property(m => m.Column1).IsRequired();
builder.Property(m => m.SubEntity.Column2).IsRequired();

我无法将所有子图的属性融入我的主要实体（我的子实体有它自己的智能）。我只是要地图我的子实体的属性，这是不存储在分隔的表，要myEntity所表

I cannot integrate all my subEntity properties into my main entity (my subEntity has its own intelligence). I just want to map my subentity properties, which is NOT stored in a separated table, to myEntity table.

最后一行抛出一个异常：

The last line throw an exception :

The expression 'm => m.SubEntity.Column2' is not a valid property expression. The expression should represent a property access: 't => t.MyProperty'.

我怎么能执行这样的映射？

How can I perform such mapping ?

推荐答案

EF核心不支持这种类型的映射现在。它不会在EF核心支持1.0 RTM（见我的github问题：）

EF Core doesn't support this type of mapping for now. It will not be supported in EF Core 1.0 RTM (see my github issue : https://github.com/aspnet/Home/issues/1330)

我在github上描述的问题，我想通了2解决方案：

As I described in my github issue, I figured out 2 solutions :

1）我的模型，specialy设计的EF创建一个派生类，并公开所有属性一样简单。这将需要更多的映射时插入/更新，并从数据库中检索。我们不选择此选项

1) Create a derived class from my model, specialy designed for EF, and expose all properties as simple. It will need more mapping when insert/update and retrieve from Db. We don't choose this option

2）创建代理属性。在我的例子，这是这样的：

2) Create proxy properties. In my example, this is like :

public class MyEntity {
   private MySubEntity SubEntity {get; set;}
   public string SubEntityValue
   {
     get
     {
         return SubEntity.Value;
     }
     set
     {
         SubEntity.Value = value;
     }
}

这似乎是最好的解决方案（我们选择了这个一个）。

This seems to be the best solution (we choose this one).

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