Question

是否有可能在不知道类型的情况下获取实体的父实体的EntityKey和类型？我尝试过以下

public partial class TestEntities
{
    partial void OnContextCreated()
    {
        this.SavingChanges += new EventHandler(logChanges);
    }

    void logChanges(object sender, EventArgs e)
    {
        IEnumerable<ObjectStateEntry> changes = this.ObjectStateManager.GetObjectStateEntries(
                                                    EntityState.Added | 
                                                    EntityState.Deleted | 
                                                    EntityState.Modified);
        TestEntities context = sender as TestEntities;

        foreach (ObjectStateEntry stateEntryEntity in changes)
        {
            if (!stateEntryEntity.IsRelationship && stateEntryEntity.Entity != null)
            {
                Audit audit = new Audit
                {
                    AuditID = Guid.NewGuid()
                };

                foreach (var relationship in stateEntryEntity.RelationshipManager.GetAllRelatedEnds())
                {
                    var parent = stateEntryEntity.RelationshipManager.GetRelatedCollection<EntityObject>(relationship.RelationshipName, relationship.TargetRoleName);
                    audit.Decription =
                        string.Format("{0} changed on {1} with id of {2}",stateEntryEntity.Entity, parent.GetType().Name);
                }

                context.AddToAudits(audit);

            }
        }
    }

}

但我得到以下内容。

An EntityCollection of EntityObject objects could not be returned for role name 
'Canine' in relationship 'TestModel.FK_CANINE'. Make sure that the 
EdmRelationshipAttribute that defines this relationship has the correct 
RelationshipMultiplicity for this role name. For more information, see the 
Entity Framework documentation.

我想知道我是否正在接近这种方式。

Answer 1

搜索后，用EF做我想做的事是不可行的。我想抓取继承树以进行审计。我最终创建了一个记录审计消息的Auditor接口。我为我想要审计的每个EF实体类型创建了Auditor实现。当调用代码要求实现Auditor接口的类时，我使用来自Microsoft Unity的命名映射来注入具体类，或者如果没有找到映射则避免审计。

查找父EntityKey并键入实体框架

1 个答案: