实体框架4 code仅错误＆QUOT;多个对象每种类型设置不支持＆QUOT; [英] Entity Framework 4 Code Only Error "Multiple objects sets per type are not supported"

问题描述

我有两个code只有POCO的使用EF4和最新的CTP，对现有的，传统的数据库上运行。运行针对PocoA LINQ查询工作，直到我加入了属性下方的对象，我想补充的关系。

I have two "Code Only" POCO's using EF4 and the latest CTP, running against an existing, legacy database. Running a LINQ query against PocoA worked until I added the property below to that object, I was trying to add a relationship.

public virtual PocoB pocoB { get; set; }

在我这样做，我开始收到以下错误：

Once I did that, I started getting the following error:

不支持每个类型的多个对象集。该对象集PocoA_DbSet'和'PocoB_DbSet可以同时包含型PocoA。实例

所以，我接下来想我的问题是因为我还没有确定的关系，而这种传统的数据库使用的是'FK / PK'preFIX，而不是一个'身份证'后缀的主键和外键。所以我增加了以下数据注解上述规定的虚方法，在行为没有改变：

So I next thought my problem was because I had not defined the relationship, and this legacy database was using a 'fk/pk' prefix instead of an 'Id' suffix on the primary and foreign keys. So I added the following data annotation to the virtual method specified above, with no change in behavior:

[RelatedTo(Property="PocoB", ForeignKey="fkPocoB")]

我真的在对什么需要改变，以使这项工作的损失。

I'm really at a loss for what needs to be changed to make this work.

推荐答案

如果你的DbContext类公开出现此错误的多个DbSet＆LT; T＆GT;其中T出现不止一次性质。基本上它不能找出哪些DbSet类型T的实例属于。

This error occurs if your DbContext class exposes multiple DbSet<T> properties where T occurs more than once. Basically it can't figure out which DbSet an instance of type T belongs to.

在code，误差大概是这样的：

In code, the error probably looked like this:

public class MyContex : DbContext {
    public DbSet<PocoA> PocoA { get; set; }
    public DbSet<PocoA> PocoB { get; set; } ...

在这里的最后一行应该是DbSet＆LT; PocoB＆GT;而不是DbSet＆LT; PocoA＆GT;

where that final line should have been DbSet<PocoB> instead of DbSet<PocoA>

这通常发生在复制和粘贴一行忘记更​​新在DbSet

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