无法使用JSON.NET序列化RelationshipManager

Question

当我尝试使用循环引用 (POCO) 序列化实体框架类时，我收到此错误。它无法序列化包含RelationshipManager 的代理类。

我尝试过此处列出的“ToList()”方法 http://json.codeplex.com/discussions/ 214093，但仍然没有运气。有什么想法吗？

这是我收到的异常的示例。

System.Reflection.TargetInvocationException was unhandled by user code
  Message=Exception has been thrown by the target of an invocation.
  Source=mscorlib
  StackTrace:
       at System.RuntimeMethodHandle._InvokeMethodFast(IRuntimeMethodInfo method, Object target, Object[] arguments, SignatureStruct& sig, MethodAttributes methodAttributes, RuntimeType typeOwner)
       at System.RuntimeMethodHandle.InvokeMethodFast(IRuntimeMethodInfo method, Object target, Object[] arguments, Signature sig, MethodAttributes methodAttributes, RuntimeType typeOwner)
       at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture, Boolean skipVisibilityChecks)
       at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
       at System.Reflection.MethodBase.Invoke(Object obj, Object[] parameters)
       at Newtonsoft.Json.Serialization.JsonContract.InvokeOnSerializing(Object o, StreamingContext context) in d:\Development\Releases\Json\Working\Src\Newtonsoft.Json\Serialization\JsonContract.cs:line 111
       at Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.SerializeObject(JsonWriter writer, Object value, JsonObjectContract contract, JsonProperty member, JsonContract collectionValueContract) in d:\Development\Releases\Json\Working\Src\Newtonsoft.Json\Serialization\JsonSerializerInternalWriter.cs:line 293
       at Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.SerializeValue(JsonWriter writer, Object value, JsonContract valueContract, JsonProperty member, JsonContract collectionValueContract) in d:\Development\Releases\Json\Working\Src\Newtonsoft.Json\Serialization\JsonSerializerInternalWriter.cs:line 117
       at Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.WriteMemberInfoProperty(JsonWriter writer, Object memberValue, JsonProperty property, JsonContract contract) in d:\Development\Releases\Json\Working\Src\Newtonsoft.Json\Serialization\JsonSerializerInternalWriter.cs:line 204
       at Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.SerializeObject(JsonWriter writer, Object value, JsonObjectContract contract, JsonProperty member, JsonContract collectionValueContract) in d:\Development\Releases\Json\Working\Src\Newtonsoft.Json\Serialization\JsonSerializerInternalWriter.cs:line 328
       at Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.SerializeValue(JsonWriter writer, Object value, JsonContract valueContract, JsonProperty member, JsonContract collectionValueContract) in d:\Development\Releases\Json\Working\Src\Newtonsoft.Json\Serialization\JsonSerializerInternalWriter.cs:line 117
       at Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.WriteMemberInfoProperty(JsonWriter writer, Object memberValue, JsonProperty property, JsonContract contract) in d:\Development\Releases\Json\Working\Src\Newtonsoft.Json\Serialization\JsonSerializerInternalWriter.cs:line 204
       at Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.SerializeObject(JsonWriter writer, Object value, JsonObjectContract contract, JsonProperty member, JsonContract collectionValueContract) in d:\Development\Releases\Json\Working\Src\Newtonsoft.Json\Serialization\JsonSerializerInternalWriter.cs:line 328
       at Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.SerializeValue(JsonWriter writer, Object value, JsonContract valueContract, JsonProperty member, JsonContract collectionValueContract) in d:\Development\Releases\Json\Working\Src\Newtonsoft.Json\Serialization\JsonSerializerInternalWriter.cs:line 117
       at Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.SerializeList(JsonWriter writer, IWrappedCollection values, JsonArrayContract contract, JsonProperty member, JsonContract collectionValueContract) in d:\Development\Releases\Json\Working\Src\Newtonsoft.Json\Serialization\JsonSerializerInternalWriter.cs:line 429
       at Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.SerializeValue(JsonWriter writer, Object value, JsonContract valueContract, JsonProperty member, JsonContract collectionValueContract) in d:\Development\Releases\Json\Working\Src\Newtonsoft.Json\Serialization\JsonSerializerInternalWriter.cs:line 127
       at Newtonsoft.Json.Serialization.JsonSerializerInternalWriter.Serialize(JsonWriter jsonWriter, Object value) in d:\Development\Releases\Json\Working\Src\Newtonsoft.Json\Serialization\JsonSerializerInternalWriter.cs:line 70
       at Newtonsoft.Json.JsonSerializer.SerializeInternal(JsonWriter jsonWriter, Object value) in d:\Development\Releases\Json\Working\Src\Newtonsoft.Json\JsonSerializer.cs:line 451
       at Newtonsoft.Json.JsonSerializer.Serialize(JsonWriter jsonWriter, Object value) in d:\Development\Releases\Json\Working\Src\Newtonsoft.Json\JsonSerializer.cs:line 443
       at Newtonsoft.Json.JsonConvert.SerializeObject(Object value, Formatting formatting, JsonSerializerSettings settings) in d:\Development\Releases\Json\Working\Src\Newtonsoft.Json\JsonConvert.cs:line 591
       at Route25.Events.API.Formatters.JsonPFormatter.OnWriteToStream(Type type, Object value, Stream stream, HttpContentHeaders contentHeaders, TransportContext context) in E:\Projects\Route25.Events\Route25.Events.API\Formatters\JsonPFormatter.cs:line 75
       at Microsoft.ApplicationServer.Http.MediaTypeFormatter.WriteToStream(Type type, Object instance, Stream stream, HttpContentHeaders contentHeaders, TransportContext context)
       at Microsoft.ApplicationServer.Http.ObjectContent.WriteToStreamInternal(Stream stream, TransportContext context)
       at Microsoft.ApplicationServer.Http.ObjectContent.SerializeToStream(Stream stream, TransportContext context)
       at System.Net.Http.HttpContent.CopyTo(Stream stream, TransportContext context)
       at System.Net.Http.HttpContent.CopyTo(Stream stream)
       at Microsoft.ApplicationServer.Http.Channels.HttpMessageEncoderFactory.HttpMessageEncoder.WriteMessage(Message message, Stream stream)
       at Microsoft.ApplicationServer.Http.Channels.HttpMessageEncoderFactory.HttpMessageEncoder.WriteMessage(Message message, Int32 maxMessageSize, BufferManager bufferManager, Int32 messageOffset)
       at System.ServiceModel.Channels.HttpOutput.SerializeBufferedMessage(Message message)
       at System.ServiceModel.Channels.HttpOutput.SendAsyncResult.SendWithoutChannelBindingToken()
       at System.ServiceModel.Channels.HttpOutput.SendAsyncResult.Send()
       at System.ServiceModel.Channels.HttpOutput.SendAsyncResult..ctor(HttpOutput httpOutput, Boolean suppressEntityBody, TimeSpan timeout, AsyncCallback callback, Object state)
       at System.ServiceModel.Channels.HttpOutput.BeginSend(TimeSpan timeout, AsyncCallback callback, Object state)
       at System.ServiceModel.Channels.HttpRequestContext.ReplyAsyncResult.SendResponse()
       at System.ServiceModel.Channels.HttpRequestContext.ReplyAsyncResult..ctor(HttpRequestContext context, Message message, TimeSpan timeout, AsyncCallback callback, Object state)
       at System.ServiceModel.Channels.HttpRequestContext.OnBeginReply(Message message, TimeSpan timeout, AsyncCallback callback, Object state)
       at System.ServiceModel.Activation.HostedHttpContext.OnBeginReply(Message message, TimeSpan timeout, AsyncCallback callback, Object state)
       at System.ServiceModel.Channels.RequestContextBase.BeginReply(Message message, TimeSpan timeout, AsyncCallback callback, Object state)
       at Microsoft.ApplicationServer.Http.Channels.HttpMessageEncodingRequestContext.BeginReply(Message message, TimeSpan timeout, AsyncCallback callback, Object state)
       at Microsoft.ApplicationServer.Http.Channels.HttpMessageHandlerChannel.ReceiveAsyncResultBase.HttpMessageHandlerRequestContext.ReplyAsyncResult.ContinueReplyPath(HttpResponseMessage httpResponse)
  InnerException: System.InvalidOperationException
       Message=The RelationshipManager object could not be serialized. This type of object cannot be serialized when the RelationshipManager belongs to an entity object that does not implement IEntityWithRelationships.
       Source=System.Data.Entity
       StackTrace:
            at System.Data.Objects.DataClasses.RelationshipManager.OnSerializing(StreamingContext context)
       InnerException: 

要复制，只需创建两个相互引用的类并使用代码优先 dbcontext 模型。

Answer 1

如果问题确实出在循环引用中，请检查此线程 寻求帮助。但是您不应该序列化您的实体 - 如果序列化程序也尝试序列化 RelationshipManager ，您应该序列化自定义对象而不是实体，因为 RelationshipManager 是实体的“基础设施”部分 - 它是不是您真正需要序列化的数据的一部分，并且很可能这部分对于您想要传递 Json 对象的目标系统没有任何意义。