不支持输入类型为“Domain.Entities.Request”的“TypeIs”表达式和“Domain.Entities.Base”类型的检查
我收到这个错误:
不支持带有“Domain.Flood.Entities.Things.SomeObject”类型输入的“TypeIs”表达式和“Domain.Entities.Base”类型的检查。 LINQ to Entities查询仅支持实体类型和复杂类型。
我正在尝试调用我的OData API并在我的对象上展开CreatedBy属性。 CreatedBy属性位于基类中,是一种User。 所以我的基类看起来像这样:
[DataContract(Namespace = "http://schemas.microsoft.com/ado/2007/08/dataservices")] public abstract class Base { [Key] [DatabaseGenerated(DatabaseGeneratedOption.Identity)] [DataMember] public int Id { get; set; } [DataMember] public string Name { get; set; } [DataMember] public string Description { get; set; } private User createdBy; [DataMember] public virtual User CreatedBy { get { return createdBy; } set { createdBy = value; } } }
当我尝试从基类inheritance我的小部件,并且我还想包含名为CreatedBy的User对象时,我收到此错误。 如果我不扩展CreatedBy对象,我不会得到错误。 这是奇怪的部分,我有另一个User属性不在基类上,而是在我的SomeObject类中称为AssignedTo。 如果我扩展它,一切都很好。 所以扩展基类上的User对象,没有bueno。 将用户对象扩展几个级别,bueno。
{ Container.SendingRequest += new EventHandler(OnSendingRequest); ViewBag.Data = Container.SomeObject.Expand("Address, CreatedBy").ToList(); return View(); }
这是堆栈跟踪:
Exception Details: System.Data.Services.Client.DataServiceClientException: An error has occurred. The 'ObjectContent`1' type failed to serialize the response body for content type 'application/atom+xml; charset=utf-8'. System.InvalidOperationException The 'TypeIs' expression with an input of type 'Domain.Flood.Entities.Things.SomeObject' and a check of type 'Domain.Entities.Base' is not supported. Only entity types and complex types are supported in LINQ to Entities queries. System.NotSupportedException at System.Data.Entity.Core.Objects.ELinq.ExpressionConverter.GetIsOrAsTargetType(ExpressionType operationType, Type toClrType, Type fromClrType)
at System.Data.Entity.Core.Objects.ELinq.ExpressionConverter.IsTranslator.TypedTranslate(ExpressionConverter parent, TypeBinaryExpression linq)
at System.Data.Entity.Core.Objects.ELinq.ExpressionConverter.TypedTranslator`1.Translate(ExpressionConverter parent, Expression linq)
at System.Data.Entity.Core.Objects.ELinq.ExpressionConverter.TranslateExpression(Expression linq)
at System.Data.Entity.Core.Objects.ELinq.ExpressionConverter.ConditionalTranslator.TypedTranslate(ExpressionConverter parent, ConditionalExpression linq)
at System.Data.Entity.Core.Objects.ELinq.ExpressionConverter.TypedTranslator`1.Translate(ExpressionConverter parent, Expression linq)
at System.Data.Entity.Core.Objects.ELinq.ExpressionConverter.TranslateExpression(Expression linq)
at System.Data.Entity.Core.Objects.ELinq.ExpressionConverter.MemberInitTranslator.TypedTranslate(ExpressionConverter parent, MemberInitExpression linq)
at System.Data.Entity.Core.Objects.ELinq.ExpressionConverter.TypedTranslator`1.Translate(ExpressionConverter parent, Expression linq)
at System.Data.Entity.Core.Objects.ELinq.ExpressionConverter.TranslateExpression(Expression linq)
at System.Data.Entity.Core.Objects.ELinq.ExpressionConverter.MemberInitTranslator.TypedTranslate(ExpressionConverter parent, MemberInitExpression linq)
at System.Data.Entity.Core.Objects.ELinq.ExpressionConverter.TypedTranslator`1.Translate(ExpressionConverter parent, Expression linq)
at System.Data.Entity.Core.Objects.ELinq.ExpressionConverter.TranslateExpression(Expression linq)
at System.Data.Entity.Core.Objects.ELinq.ExpressionConverter.MemberInitTranslator.TypedTranslate(ExpressionConverter parent, MemberInitExpression linq)
at System.Data.Entity.Core.Objects.ELinq.ExpressionConverter.TypedTranslator`1.Translate(ExpressionConverter parent, Expression linq)
at System.Data.Entity.Core.Objects.ELinq.ExpressionConverter.TranslateExpression(Expression linq)
at System.Data.Entity.Core.Objects.ELinq.ExpressionConverter.TranslateLambda(LambdaExpression lambda, DbExpression input)
at System.Data.Entity.Core.Objects.ELinq.ExpressionConverter.TranslateLambda(LambdaExpression lambda, DbExpression input, DbExpressionBinding& binding)
at System.Data.Entity.Core.Objects.ELinq.ExpressionConverter.MethodCallTranslator.OneLambdaTranslator.Translate(ExpressionConverter parent, MethodCallExpression call, DbExpression& source, DbExpressionBinding& sourceBinding, DbExpression& lambda)
at System.Data.Entity.Core.Objects.ELinq.ExpressionConverter.MethodCallTranslator.SelectTranslator.Translate(ExpressionConverter parent, MethodCallExpression call)
at System.Data.Entity.Core.Objects.ELinq.ExpressionConverter.MethodCallTranslator.SequenceMethodTranslator.Translate(ExpressionConverter parent, MethodCallExpression call, SequenceMethod sequenceMethod)
at System.Data.Entity.Core.Objects.ELinq.ExpressionConverter.MethodCallTranslator.TypedTranslate(ExpressionConverter parent, MethodCallExpression linq)
at System.Data.Entity.Core.Objects.ELinq.ExpressionConverter.TypedTranslator`1.Translate(ExpressionConverter parent, Expression linq)
at System.Data.Entity.Core.Objects.ELinq.ExpressionConverter.TranslateExpression(Expression linq)
at System.Data.Entity.Core.Objects.ELinq.ExpressionConverter.Convert()
at System.Data.Entity.Core.Objects.ELinq.ELinqQueryState.GetExecutionPlan(Nullable`1 forMergeOption)
at System.Data.Entity.Core.Objects.ObjectQuery`1.<>c__DisplayClassb.<GetResults>b__a()
at System.Data.Entity.Core.Objects.ObjectContext.ExecuteInTransaction[T](Func`1 func, IDbExecutionStrategy executionStrategy, Boolean startLocalTransaction, Boolean releaseConnectionOnSuccess)
at System.Data.Entity.Core.Objects.ObjectQuery`1.<>c__DisplayClassb.<GetResults>b__9()
at System.Data.Entity.SqlServer.DefaultSqlExecutionStrategy.Execute[TResult](Func`1 operation)
at System.Data.Entity.Core.Objects.ObjectQuery`1.GetResults(Nullable`1 forMergeOption)
at System.Data.Entity.Core.Objects.ObjectQuery`1.<System.Collections.Generic.IEnumerable<T>.GetEnumerator>b__0()
at System.Lazy`1.CreateValue()
at System.Lazy`1.LazyInitValue()
at System.Lazy`1.get_Value()
at System.Data.Entity.Internal.LazyEnumerator`1.MoveNext()
at System.Web.Http.OData.Formatter.Serialization.ODataFeedSerializer.WriteFeed(IEnumerable enumerable, IEdmTypeReference feedType, ODataWriter writer, ODataSerializerContext writeContext)
at System.Web.Http.OData.Formatter.Serialization.ODataFeedSerializer.WriteObjectInline(Object graph, IEdmTypeReference expectedType, ODataWriter writer, ODataSerializerContext writeContext)
at System.Web.Http.OData.Formatter.Serialization.ODataFeedSerializer.WriteObject(Object graph, Type type, ODataMessageWriter messageWriter, ODataSerializerContext writeContext)
at System.Web.Http.OData.Formatter.ODataMediaTypeFormatter.WriteToStream(Type type, Object value, Stream writeStream, HttpContent content, HttpContentHeaders contentHeaders)
at System.Web.Http.OData.Formatter.ODataMediaTypeFormatter.WriteToStreamAsync(Type type, Object value, Stream writeStream, HttpContent content, TransportContext transportContext)
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at System.Runtime.CompilerServices.TaskAwaiter.GetResult()
at System.Web.Http.WebHost.HttpControllerHandler.<WriteBufferedResponseContentAsync>d__14.MoveNext()
阅读错误消息,我可以看到Linq to Entities正试图将一件事转换成另一件事,但到目前为止,我真的不知道。
我注意到的另一件事是我的OData元数据显示了所有内容,而不仅仅是具有数据合同的内容。 它过去只包含具有数据合同的类。 这有点奇怪吧? 我浏览了我的源代码控制,看看在最后几个更改集中发生了什么变化,我没有看到任何与我的Base类,Users类或我的SomeObject类有关的内容。 与我的API无关。
如果我能更清楚,请告诉我。 我觉得我要留下一些东西。
如果您仔细阅读错误:
‘TypeIs’表达式,输入类型为’Domain.Flood.Entities.Things。 SomeObject ‘和’Domain.Entities类型的检查。 Base ‘不受支持。
这意味着OData尝试一个查询,使得EF生成一个具有“TypeIs”function的查询本身很好,但TypeIs的两个操作数必须是实体类型或复杂类型:
LINQ to Entities查询仅支持实体类型和复杂类型 。
也就是说,在EF DbContext中,使用模型构建器,您必须确保上下文将SomeObject和Base都知道为实体类型或复杂类型。 这是用Fluent API做的:
protected override void OnModelCreating(DbModelBuilder modelBuilder) { modelBuilder.Entity (); //EF should crawl and configure all derived types as well. }
另外,使用DbModelBuilder.Ignore()时要特别注意不要忽略任何重要类型。
更新:
您还可以告诉OData将所有超类inheritance的属性视为ODataConventionModelBuilder
的inheritance类型:
使用System.Web.OData
:
modelBuilder.EntityType().DerivesFromNothing();
使用System.Web.Http.OData
:
modelBuilder.Entity().DerivesFromNothing();