阅读外键编程的元数据与实体框架4 [英] Read foreign key metadata programatically with Entity Framework 4

问题描述

有谁知道如何人去有关获取模式的信息产生出实体框架？一个EDMX的

Does anyone know how one goes about obtaining the schema information out of an edmx generated Entity Framework?

具体来说，我要管理遍历了，我目前没有实例的实体的外键，并获得它的外键关系，我想通过反射的方式，将是一般要做到这一点适用于任何实体类没有定制$ C $每次℃。

Specifically I want to manage to traverse the foreign key for an entity that I don't currently have an instance of and get the it's foreign key relationships, and I want to do this via reflection in a way that'll be generically applied to any entity class without custom code each time.

EG：我的架构中有2类，用户和组。我有数字42，我知道从用户实体的GroupId物业来了，但此刻我不知道如何来检测的用户外键这个GroupId的财产它由集团实体的GroupId属性。

EG: My schema has 2 classes, User and Group. I have the number "42" that I know came from the "GroupId" property of a "User" entity, but at the moment I can't work out how to detect that this "GroupId" property of "User" foreign keys to the "Group" entity by it's "GroupId" property.

推荐答案

最终找到了解决这个。相关信息可在上下文中的 RelationshipManager 属性来找到。通过调用 GetAllRelatedEnds（），然后找到的类型的人 AssociationSet 。

Ended up finding the solution to this. The relevant information can be found in the context's RelationshipManager property. By calling GetAllRelatedEnds() and then finding the ones of the type AssociationSet.

的的ElementType 的关联设置则包含一个 IsForeignKey 属性，并且还数组 ReferentialConstraints 具有属性每个约束 ToRole ， ToProperty ， FromRole 和 FromProperty 分别与 RelationshipMultiplicity 在 ToRole / FromRole 可用于确定外键关系的方向。

The ElementType of the association set then contains an IsForeignKey property and also an array ReferentialConstraints that has properties for each constraint ToRole, ToProperty, FromRole and FromProperty respectively, and the RelationshipMultiplicity on the ToRole/FromRole can be used to determine the direction of the foreign key relationship.

把所有这些数据，并使用上下文的 GetObjectByKey 方法，我能够以编程方式遍历的上下文定义的外键关系，而无需关联实体。

Taking all this data and using the context's GetObjectByKey method I was able to programatically traverse the foreign key relationships defined for a context without having the associated entity.

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