Question

我们在应用程序中的特定查询中遇到此错误大概有三次：

The property 'Id' is part of the object's key information and cannot be modified.

at System.Data.Entity.Core.Objects.EntityEntry.VerifyEntityValueIsEditable(StateManagerTypeMetadata typeMetadata, Int32 ordinal, String memberName)
at System.Data.Entity.Core.Objects.EntityEntry.GetAndValidateChangeMemberInfo(String entityMemberName, Object complexObject, String complexObjectMemberName, StateManagerTypeMetadata& typeMetadata, String& changingMemberName, Object& changingObject)
at System.Data.Entity.Core.Objects.EntityEntry.EntityMemberChanging(String entityMemberName, Object complexObject, String complexObjectMemberName)
at System.Data.Entity.Core.Objects.EntityEntry.EntityMemberChanging(String entityMemberName)
at System.Data.Entity.Core.Objects.ObjectStateEntry.System.Data.Entity.Core.Objects.DataClasses.IEntityChangeTracker.EntityMemberChanging(String entityMemberName)
at System.Data.Entity.Core.Objects.Internal.SnapshotChangeTrackingStrategy.SetCurrentValue(EntityEntry entry, StateManagerMemberMetadata member, Int32 ordinal, Object target, Object value)
at System.Data.Entity.Core.Objects.Internal.EntityWrapper`1.SetCurrentValue(EntityEntry entry, StateManagerMemberMetadata member, Int32 ordinal, Object target, Object value)
at System.Data.Entity.Core.Objects.DataClasses.EntityReference.UpdateForeignKeyValues(IEntityWrapper dependentEntity, IEntityWrapper principalEntity, Dictionary`2 changedFKs, Boolean forceChange)
at System.Data.Entity.Core.Objects.DataClasses.EntityReference.UpdateDependentEndForeignKey(RelatedEnd targetRelatedEnd, Boolean forceForeignKeyChanges)
at System.Data.Entity.Core.Objects.DataClasses.RelatedEnd.Add(IEntityWrapper wrappedTarget, Boolean applyConstraints, Boolean addRelationshipAsUnchanged, Boolean relationshipAlreadyExists, Boolean allowModifyingOtherEndOfRelationship, Boolean forceForeignKeyChanges)
at System.Data.Entity.Core.Objects.DataClasses.RelatedEnd.Add(IEntityWrapper wrappedEntity, Boolean applyConstraints)
at System.Data.Entity.Core.Objects.DataClasses.EntityReference`1.set_ReferenceValue(IEntityWrapper value)
at System.Data.Entity.Core.Objects.DataClasses.EntityReference.SetEntityKey(EntityKey value, Boolean forceFixup)
at System.Data.Entity.Core.Objects.EntityEntry.FixupEntityReferenceToPrincipal(EntityReference relatedEnd, EntityKey foreignKey, Boolean setIsLoaded, Boolean replaceExistingRef)
at System.Data.Entity.Core.Objects.EntityEntry.FixupReferencesByForeignKeys(Boolean replaceAddedRefs, EntitySetBase restrictTo)
at System.Data.Entity.Core.Objects.ObjectStateManager.FixupReferencesByForeignKeys(EntityEntry newEntry, Boolean replaceAddedRefs)
at System.Data.Entity.Core.Objects.ObjectStateManager.AddEntry(IEntityWrapper wrappedObject, EntityKey passedKey, EntitySet entitySet, String argumentName, Boolean isAdded)
at System.Data.Entity.Core.Common.Internal.Materialization.Shaper.HandleEntity[TEntity](IEntityWrapper wrappedEntity, EntityKey entityKey, EntitySet entitySet)
at lambda_method(Closure , Shaper )
at System.Data.Entity.Core.Common.Internal.Materialization.Coordinator`1.ReadNextElement(Shaper shaper)
at System.Data.Entity.Core.Common.Internal.Materialization.Shaper`1.RowNestedResultEnumerator.MaterializeRow()
at System.Data.Entity.Core.Common.Internal.Materialization.Shaper`1.RowNestedResultEnumerator.MoveNext()
at System.Data.Entity.Core.Common.Internal.Materialization.Shaper`1.ObjectQueryNestedEnumerator.TryReadToNextElement()
at System.Data.Entity.Core.Common.Internal.Materialization.Shaper`1.ObjectQueryNestedEnumerator.ReadElement()
at System.Data.Entity.Core.Common.Internal.Materialization.Shaper`1.ObjectQueryNestedEnumerator.MoveNext()
at System.Data.Entity.Internal.LazyEnumerator`1.MoveNext()
at System.Collections.Generic.List`1..ctor(IEnumerable`1 collection)
at System.Linq.Enumerable.ToList[TSource](IEnumerable`1 source)
....project specific stack elements

有问题的查询是一个简单的选择查询：

var set = ObjectContext.CreateObjectSet<TModel>();
set = set.WithMergeOption(MergeOption.OverwriteChanges)
var results = set.Where(p => (!p.IsArchived && !p.IsDeleted))
    .Include(w => w.CurrentPlaceStructure)
    .Include(o => o.Room.Wing.Location)
    .Include(r => r.Residencies)
    .Include(r => r.PlaceStructures)
    .Include(r => r.Room.RoomStructures)
    .ToList();

错误消息＆amp;谷歌建议尝试修改Id值时会发生此错误。但是这只是一个select语句，我们不会修改此查询中的任何内容。请注意，在此之前，其他查询已在DbContext上运行，因此其他对象可能已在上下文中。

为什么会在select语句中出现？

为什么它只会在每3次出现一次？

哪些复合因素可能会导致此错误消息？

Answer 1

我找到了原因。

事实证明，在多个线程中同时使用了相同的DbContext。 EF6对于此用途不是线程安全的，因此发生了随机内部错误。

该物业＆＃39; Id＆＃39;是对象的关键信息的一部分，无法在SELECT上修改

1 个答案: