Unable to serialize RelationshipManager with JSON.NET

I receive this error when I am trying to serialise a entity framework class with a circular reference (POCO). It is unable to serialise the proxy class which contains a RelationshipManager.

I have tried to the 'ToList()' method listed here http://json.codeplex.com/discussions/214093, but still no luck. Any ideas?

Here is an example of the exception i am receiving.

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, O开发者_如何学Pythonbject 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: 

To replicate simply create two classes that reference each other and use the code-first dbcontext model.

If the problem really is in circular references check this thread for help. But you should not serialize your entities - if serializer tries to serialize RelationshipManager as well you should serialize custom objects instead of entities because RelationshipManager is "infrastructure" part of entity - it is not part of data you really need to serialize and most probably this part has no meaning for target system where you want to pass Json object.