Fix for - A circular reference was detected while serializing an object of type 'System.RuntimeType'

I recently had a problem with the Circular reference when I was trying to serialize my Response in Json format. I was calling the Serializer for the object like this new JavaScriptSerializer().Serialize(ResponseTransaction) And my class looked like below.

    [DataContract]
    public abstract class BaseResponse
    {
        [DataMember]
        public APIReturn ResponseCode { get; set; }

        [DataMember]
        public string ResponseMessage { get; set; }

        public Exception OperationException { get; set; }
    }

Basically what is happening is Json does not like to have circular reference ie. Class A -> Class B -> Class A

Error Message I was getting: A circular reference was detected while serializing an object of type 'System.RuntimeType'. Stack Trace:  at System.Web.Script.Serialization.JavaScriptSerializer.SerializeValueInternal(Object o, StringBuilder sb, Int32 depth, Hashtable objectsInUse, SerializationFormat serializationFormat, MemberInfo currentMember) at System.Web.Script.Serialization.JavaScriptSerializer.SerializeValue(Object o, StringBuilder sb, Int32 depth, Hashtable objectsInUse, SerializationFormat serializationFormat, MemberInfo currentMember) at System.Web.Script.Serialization.JavaScriptSerializer.SerializeEnumerable(IEnumerable enumerable, StringBuilder sb, Int32 depth, Hashtable objectsInUse, SerializationFormat serializationFormat) at System.Web.Script.Serialization.JavaScriptSerializer.SerializeValueInternal(Object o, StringBuilder sb, Int32 depth, Hashtable objectsInUse, SerializationFormat serializationFormat, MemberInfo currentMember) at System.Web.Script.Serialization.JavaScriptSerializer.SerializeValue(Object o, StringBuilder sb, Int32 depth, Hashtable objectsInUse, SerializationFormat serializationFormat, MemberInfo currentMember) at System.Web.Script.Serialization.JavaScriptSerializer.SerializeCustomObject(Object o, StringBuilder sb, Int32 depth, Hashtable objectsInUse, SerializationFormat serializationFormat) at System.Web.Script.Serialization.JavaScriptSerializer.SerializeValueInternal(Object o, StringBuilder sb, Int32 depth, Hashtable objectsInUse, SerializationFormat serializationFormat, MemberInfo currentMember) at System.Web.Script.Serialization.JavaScriptSerializer.SerializeValue(Object o, StringBuilder sb, Int32 depth, Hashtable objectsInUse, SerializationFormat serializationFormat, MemberInfo currentMember) at System.Web.Script.Serialization.JavaScriptSerializer.SerializeCustomObject(Object o, StringBuilder sb, Int32 depth, Hashtable objectsInUse, SerializationFormat serializationFormat) at System.Web.Script.Serialization.JavaScriptSerializer.SerializeValueInternal(Object o, StringBuilder sb, Int32 depth, Hashtable objectsInUse, SerializationFormat serializationFormat, MemberInfo currentMember) at System.Web.Script.Serialization.JavaScriptSerializer.SerializeValue(Object o, StringBuilder sb, Int32 depth, Hashtable objectsInUse, SerializationFormat serializationFormat, MemberInfo currentMember) at System.Web.Script.Serialization.JavaScriptSerializer.SerializeCustomObject(Object o, StringBuilder sb, Int32 depth, Hashtable objectsInUse, SerializationFormat serializationFormat) at System.Web.Script.Serialization.JavaScriptSerializer.SerializeValueInternal(Object o, StringBuilder sb, Int32 depth, Hashtable objectsInUse, SerializationFormat serializationFormat, MemberInfo currentMember) at System.Web.Script.Serialization.JavaScriptSerializer.SerializeValue(Object o, StringBuilder sb, Int32 depth, Hashtable objectsInUse, SerializationFormat serializationFormat, MemberInfo currentMember) at System.Web.Script.Serialization.JavaScriptSerializer.SerializeCustomObject(Object o, StringBuilder sb, Int32 depth, Hashtable objectsInUse, SerializationFormat serializationFormat) at System.Web.Script.Serialization.JavaScriptSerializer.SerializeValueInternal(Object o, StringBuilder sb, Int32 depth, Hashtable objectsInUse, SerializationFormat serializationFormat, MemberInfo currentMember) at System.Web.Script.Serialization.JavaScriptSerializer.SerializeValue(Object o, StringBuilder sb, Int32 depth, Hashtable objectsInUse, SerializationFormat serializationFormat, MemberInfo currentMember) at System.Web.Script.Serialization.JavaScriptSerializer.SerializeCustomObject(Object o, StringBuilder sb, Int32 depth, Hashtable objectsInUse, SerializationFormat serializationFormat) at System.Web.Script.Serialization.JavaScriptSerializer.SerializeValueInternal(Object o, StringBuilder sb, Int32 depth, Hashtable objectsInUse, SerializationFormat serializationFormat, MemberInfo currentMember) at System.Web.Script.Serialization.JavaScriptSerializer.SerializeValue(Object o, StringBuilder sb, Int32 depth, Hashtable objectsInUse, SerializationFormat serializationFormat, MemberInfo currentMember) at System.Web.Script.Serialization.JavaScriptSerializer.SerializeCustomObject(Object o, StringBuilder sb, Int32 depth, Hashtable objectsInUse, SerializationFormat serializationFormat) at System.Web.Script.Serialization.JavaScriptSerializer.SerializeValueInternal(Object o, StringBuilder sb, Int32 depth, Hashtable objectsInUse, SerializationFormat serializationFormat, MemberInfo currentMember) at System.Web.Script.Serialization.JavaScriptSerializer.SerializeValue(Object o, StringBuilder sb, Int32 depth, Hashtable objectsInUse, SerializationFormat serializationFormat, MemberInfo currentMember) at System.Web.Script.Serialization.JavaScriptSerializer.Serialize(Object obj, StringBuilder output, SerializationFormat serializationFormat) at System.Web.Script.Serialization.JavaScriptSerializer.Serialize(Object obj, SerializationFormat serializationFormat) at System.Web.Script.Serialization.JavaScriptSerializer.Serialize(Object obj) at JXTPlatform.API.Implementation.ServiceBase.LoggingOperationTransaction[R,RS](String method, R RequestTransaction, RS ResponseTransaction) in C:\Developments\JXT_API\JXTPlatformAPI\Implementation\Base\ServiceBase.cs:line 151 at JXTPlatform.API.Implementation.MemberLoginService.Execute(MemberLoginRequest request) in C:\Developments\JXT_API\JXTPlatformAPI\Implementation\Member\MemberLoginService.cs:line 68 at ServiceStack.ServiceHost.ServiceExec`1.Execute(IService`1 service, TReq request, EndpointAttributes attrs) at lambda_method(Closure , Object , Object , EndpointAttributes ) at ServiceStack.ServiceHost.ServiceController.<>c__DisplayClass9.<>c__DisplayClassb.<RegisterGServiceExecutor>b__8(IRequestContext reqCtx, Object req) at ServiceStack.ServiceHost.ServiceController.ManagedServiceExec(ServiceExecFn serviceExec, Object service, IRequestContext requestContext, Object dto) at ServiceStack.ServiceHost.ServiceController.<>c__DisplayClass9.<RegisterGServiceExecutor>b__7(IRequestContext requestContext, Object dto) at ServiceStack.ServiceHost.ServiceController.Execute(Object request, IRequestContext requestContext) at ServiceStack.WebHost.Endpoints.EndpointHost.ExecuteService(Object request, EndpointAttributes endpointAttributes, IHttpRequest httpReq, IHttpResponse httpRes) at ServiceStack.WebHost.Endpoints.Support.EndpointHandlerBase.ExecuteService(Object request, EndpointAttributes endpointAttributes, IHttpRequest httpReq, IHttpResponse httpRes) at ServiceStack.WebHost.Endpoints.RestHandler.GetResponse(IHttpRequest httpReq, IHttpResponse httpRes, Object request) at ServiceStack.WebHost.Endpoints.RestHandler.ProcessRequest(IHttpRequest httpReq, IHttpResponse httpRes, String operationName)

Solution:

The easiest fix is to use [ScriptIgnore] in your Class property to tell not to serialize object that may cause such a circulate issue. Add the System.Web.Extensions reference to your Project and make the elements that may cause issue to [ScriptIgnore] So now my class looked like this.

    [DataContract]
    public abstract class BaseResponse
    {
        [DataMember]
        [ScriptIgnore]
        public APIReturn ResponseCode { get; set; }

        [DataMember]
        [ScriptIgnore]
        public string ResponseMessage { get; set; }

        public Exception OperationException { get; set; }

    }

Thats it :)