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使用 Entity Framework Code First (4.1) 调用 System.Data.Entity.DbContext.GetValidationErrors() 时出现以下异常

"An item with the same key has already been added."

堆栈跟踪如下：

at System.Collections.Generic.Dictionary`2.Insert(TKey key, TValue value, Boolean add)
at System.Data.Metadata.Edm.ObjectItemConventionAssemblyLoader.TryCreateType(Type type, StructuralType cspaceType, EdmType& newOSpaceType)
at System.Data.Metadata.Edm.ObjectItemConventionAssemblyLoader.LoadTypesFromAssembly()
at System.Data.Metadata.Edm.ObjectItemAssemblyLoader.Load()
at System.Data.Metadata.Edm.ObjectItemAssemblyLoader.LoadAssemblies(IEnumerable`1 assemblies, ObjectItemLoadingSessionData sessionData)
at System.Data.Metadata.Edm.AssemblyCache.LoadAssembly(Assembly assembly, Boolean loadReferencedAssemblies, ObjectItemLoadingSessionData loadingData)
at System.Data.Metadata.Edm.AssemblyCache.LoadAssembly(Assembly assembly, Boolean loadReferencedAssemblies, KnownAssembliesSet knownAssemblies, EdmItemCollection edmItemCollection, Action`1 logLoadMessage, Object& loaderCookie, Dictionary`2& typesInLoading, List`1& errors)
at System.Data.Metadata.Edm.ObjectItemCollection.LoadAssemblyFromCache(ObjectItemCollection objectItemCollection, Assembly assembly, Boolean loadReferencedAssemblies, EdmItemCollection edmItemCollection, Action`1 logLoadMessage)
at System.Data.Metadata.Edm.ObjectItemCollection.ExplicitLoadFromAssembly(Assembly assembly, EdmItemCollection edmItemCollection, Action`1 logLoadMessage)
at System.Data.Metadata.Edm.MetadataWorkspace.ExplicitLoadFromAssembly(Assembly assembly, ObjectItemCollection collection, Action`1 logLoadMessage)
at System.Data.Entity.Infrastructure.DbCompiledModel.CreateObjectContext[TContext](DbConnection existingConnection)
at System.Data.Entity.Internal.LazyInternalContext.InitializeContext()
at System.Data.Entity.Internal.LazyInternalContext.get_ObjectContext()
at System.Data.Entity.Internal.InternalContext.DetectChanges(Boolean force)
at System.Data.Entity.Internal.InternalContext.GetStateEntries(Func`2 predicate)
at System.Data.Entity.DbContext.GetValidationErrors()

不幸的是，我无法确定问题出在哪里，也无法确定是哪个 poco 实体造成的。

有人有线索吗？

谢谢

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1 回答 1

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是的，这是一个有趣的问题，这里的问题来自尝试重新附加一个已经附加到上下文的实体。这可能来自逻辑错误，或者您可能在未清除附加对象的情况下重用上下文。数据库上有一个本地集合，您可以使用它来查看当前附加到上下文的项目。

ctx.YourEntityCollection.Local
于 2012-08-03T12:49:57.920 回答