Question

我有一个项目，我正在使用STE（EF4.1），当我在我的一个对象集上调用自动生成的ApplyChanges（）方法时，我遇到了一个可重现的问题，传入了一个我有的对象图保存在内存中，我收到以下错误：

InvalidOperationException: 
    Collection was modified; enumeration operation may not execute.

这源于对ObjectContext.AddObject（）方法的调用，该方法由T4自动生成的ApplyChanges（）方法调用。我调用ApplyChanges的方法如下所示：

// Extension to auto generated Session : IObjectWithChangeTracker
public partial class Session
{
    public void SaveToDatabase(String myConnectionString)
    { 
        using (MyContext DbContext = new MyContext(myConnectionString))
        {
            DbContext.Sessions.ApplyChanges(this);
            DbContext.SaveChanges();
        }
    }
}

我遇到错误时的调用堆栈看起来像这样：

at System.ThrowHelper.ThrowInvalidOperationException(ExceptionResource resource)
at System.Collections.Generic.List`1.Enumerator.MoveNextRare()
at System.Collections.Generic.List`1.Enumerator.MoveNext()
at System.Data.Objects.DataClasses.RelatedEnd.WalkObjectGraphToIncludeAllRelatedEntities(IEntityWrapper wrappedEntity, Boolean addRelationshipAsUnchanged, Boolean doAttach)
at System.Data.Objects.DataClasses.RelatedEnd.AddGraphToObjectStateManager(IEntityWrapper wrappedEntity, Boolean relationshipAlreadyExists, Boolean addRelationshipAsUnchanged, Boolean doAttach)
at System.Data.Objects.DataClasses.RelatedEnd.IncludeEntity(IEntityWrapper wrappedEntity, Boolean addRelationshipAsUnchanged, Boolean doAttach)
at System.Data.Objects.DataClasses.EntityReference`1.Include(Boolean addRelationshipAsUnchanged, Boolean doAttach)
... // The below 4 lines are pretty much repeated as it iterates through the object graph
at System.Data.Objects.DataClasses.RelatedEnd.WalkObjectGraphToIncludeAllRelatedEntities(IEntityWrapper wrappedEntity, Boolean addRelationshipAsUnchanged, Boolean doAttach)
at System.Data.Objects.DataClasses.RelatedEnd.AddGraphToObjectStateManager(IEntityWrapper wrappedEntity, Boolean relationshipAlreadyExists, Boolean addRelationshipAsUnchanged, Boolean doAttach)
at System.Data.Objects.DataClasses.RelatedEnd.IncludeEntity(IEntityWrapper wrappedEntity, Boolean addRelationshipAsUnchanged, Boolean doAttach)
at System.Data.Objects.DataClasses.EntityCollection`1.Include(Boolean addRelationshipAsUnchanged, Boolean doAttach)
at System.Data.Objects.DataClasses.RelatedEnd.WalkObjectGraphToIncludeAllRelatedEntities(IEntityWrapper wrappedEntity, Boolean addRelationshipAsUnchanged, Boolean doAttach)
at System.Data.Objects.DataClasses.RelatedEnd.AddGraphToObjectStateManager(IEntityWrapper wrappedEntity, Boolean relationshipAlreadyExists, Boolean addRelationshipAsUnchanged, Boolean doAttach)
at System.Data.Objects.DataClasses.RelatedEnd.IncludeEntity(IEntityWrapper wrappedEntity, Boolean addRelationshipAsUnchanged, Boolean doAttach)
at System.Data.Objects.DataClasses.EntityReference`1.Include(Boolean addRelationshipAsUnchanged, Boolean doAttach)
at System.Data.Objects.DataClasses.RelationshipManager.AddRelatedEntitiesToObjectStateManager(Boolean doAttach)
at System.Data.Objects.ObjectContext.AddObject(String entitySetName, Object entity)
at MyNamespace.SelfTrackingEntitiesContextExtensions.AddHelper.AddAllEntities(ObjectContext context, String entitySetName, IObjectWithChangeTracker entity)
at MyNamespace.SelfTrackingEntitiesContextExtensions.ApplyChanges[TEntity](ObjectContext context, String entitySetName, TEntity entity)
at MyNamespace.SelfTrackingEntitiesContextExtensions.ApplyChanges[TEntity](ObjectSet`1 objectSet, TEntity entity) 
at MyNamespace.Transaction.SaveToDatabase(String transactionDbConnectionString)

当操作正在进行时，我根本没有修改对象图，所以我真的很难过这个问题。有人有任何想法吗？

由于

Answer 1

我们遇到了同样的问题。我们可以通过删除导航属性来解决它，以便它们不能以圆圈运行。因此，如果A将B作为导航属性，则B不应该将A作为导航属性。在所有情况下都不可能，但在我们的情况下，它解决了这个问题。

Answer 2

有同样的问题。看起来像是在.net 4.5中修复的错误。

T4生成的助手方法SelfTrackingModel.Context.Extensions中的InvalidOperation

2 个答案: