"A circular reference was detected while serializing an object of type 'System.Data.Entity.DynamicProxies.Category" in v2.8

I am getting an error of The Requested URL returned 500 when attempting any search or refresh of my customer list in the admin (/Admin/Customer/List).   I have about 250 customers (and am able to load all of them without error when I set the admin grid size to 250+).  If I set the grid size to 200, I can move to page 2 (using the pagination toolbar) but then if I attempt to return to page 1 I get the error (my first thought was bad data in one of the customer records but it doesn't make sense since I can view them all).  Anyway any suggestions of where I should look would be appreciated.    I am in version 2.8 currently.  

The following is from the System Log...

The level of log entry.Log level:   Error
The log entry message.Short message:   A circular reference was detected while serializing an object of type 'System.Data.Entity.DynamicProxies.Category_2458A300BAB1AECE79EA2650009261BBB53D34426E43A21D9DF343904903F5CC'.
The details for the log entry.Full message:   System.InvalidOperationException: A circular reference was detected while serializing an object of type 'System.Data.Entity.DynamicProxies.Category_2458A300BAB1AECE79EA2650009261BBB53D34426E43A21D9DF343904903F5CC'. 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.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.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.SerializeDictionary(IDictionary 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 System.Web.Mvc.JsonResult.ExecuteResult(ControllerContext context) at System.Web.Mvc.ControllerActionInvoker.InvokeActionResult(ControllerContext controllerContext, ActionResult actionResult) at System.Web.Mvc.ControllerActionInvoker.<>c__DisplayClass1a.<InvokeActionResultWithFilters>b__17() at System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilter(IResultFilter filter, ResultExecutingContext preContext, Func`1 continuation) at System.Web.Mvc.ControllerActionInvoker.<>c__DisplayClass1a.<>c__DisplayClass1c.<InvokeActionResultWithFilters>b__19() at System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilter(IResultFilter filter, ResultExecutingContext preContext, Func`1 continuation) at System.Web.Mvc.ControllerActionInvoker.<>c__DisplayClass1a.<>c__DisplayClass1c.<InvokeActionResultWithFilters>b__19() at System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilter(IResultFilter filter, ResultExecutingContext preContext, Func`1 continuation) at System.Web.Mvc.ControllerActionInvoker.<>c__DisplayClass1a.<>c__DisplayClass1c.<InvokeActionResultWithFilters>b__19() at System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilter(IResultFilter filter, ResultExecutingContext preContext, Func`1 continuation) at System.Web.Mvc.ControllerActionInvoker.<>c__DisplayClass1a.<>c__DisplayClass1c.<InvokeActionResultWithFilters>b__19() at System.Web.Mvc.ControllerActionInvoker.InvokeActionResultWithFilters(ControllerContext controllerContext, IList`1 filters, ActionResult actionResult) at System.Web.Mvc.Async.AsyncControllerActionInvoker.<>c__DisplayClass25.<>c__DisplayClass2a.<BeginInvokeAction>b__20() at System.Web.Mvc.Async.AsyncControllerActionInvoker.<>c__DisplayClass25.<BeginInvokeAction>b__22(IAsyncResult asyncResult) at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResult`1.End() at System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeAction(IAsyncResult asyncResult) at System.Web.Mvc.Controller.<>c__DisplayClass1d.<BeginExecuteCore>b__18(IAsyncResult asyncResult) at System.Web.Mvc.Async.AsyncResultWrapper.<>c__DisplayClass4.<MakeVoidDelegate>b__3(IAsyncResult ar) at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResult`1.End() at System.Web.Mvc.Controller.EndExecuteCore(IAsyncResult asyncResult) at System.Web.Mvc.Async.AsyncResultWrapper.<>c__DisplayClass4.<MakeVoidDelegate>b__3(IAsyncResult ar) at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResult`1.End() at System.Web.Mvc.Controller.EndExecute(IAsyncResult asyncResult) at System.Web.Mvc.Controller.System.Web.Mvc.Async.IAsyncController.EndExecute(IAsyncResult asyncResult) at System.Web.Mvc.MvcHandler.<>c__DisplayClass8.<BeginProcessRequest>b__3(IAsyncResult asyncResult) at System.Web.Mvc.Async.AsyncResultWrapper.<>c__DisplayClass4.<MakeVoidDelegate>b__3(IAsyncResult ar) at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResult`1.End() at System.Web.Mvc.MvcHandler.EndProcessRequest(IAsyncResult asyncResult) at System.Web.Mvc.MvcHandler.System.Web.IHttpAsyncHandler.EndProcessRequest(IAsyncResult result) at System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)

I know this is a bit late, but maybe it will help someone else.

Go take a look at the navigation property for Category...  I bet that chances are that you have obj.Category, when you may have meant obj.Category.CategoryName or something similar...

;-)  I had the same issue a while back and I beat my head on the table when I realized what I had done.

v/r
BK

Hi everyone,
I am receiving following error when I try to serialize the List;

A circular reference was detected while serializing an object of type 'System.Data.Entity.DynamicProxies.CustomerRole_A964A0809AA55199114F2C501957F4347FE922951F67AD696E55F7B9CCA63243'.

My structure is:

I have CustomerXXX.cs have a relationship with Customer.cs and gets customer Id and XXXXInfo.cs have a relationship with CustomerXXX.cs getting xxx Id. All have foreign keys with each other on database.

on my CustomerXXX service I get the XXX by customer Id as follow;

 public virtual IList<CustomerXXX> GetXXXsByCustomerId(int? customerId)
        {
            var query = from pc in _shipRepository.Table
                        where pc.Customer_Id == customerId
                        select pc;
            var result = new List<CustomerXXX>(query);

            return result;
        }

and on my XXXInfo service, I get the XXXInfo (s) by Customers as follow;

public virtual IList<List<XXXInfo>> GetLatestXXXInfoByCustomerId(int customerId)
        {
            IList<List<XXXInfo>> result = new List<List<XXXInfo>>();
            var xxxs = EngineContext.Current.Resolve<ICustomerXXXService>().GetXXXsByCustomerId(customerId);
            foreach (var pr in xxxs)
            {

                var lastinfo = GetLastXXXTime(pr.Id);
                var query = (from pc in _xxxInfoRepository.Table
                             where pc.XXX_Id == pr.Id && pc.XXXUtc == lastinfo
                             select pc).ToList();
                result.Add(query);
            }

            return result;
        }

and on my controller;

public JsonResult GetMarkers()
        {
            var customer = EngineContext.Current.Resolve<IWorkContext>().CurrentCustomer;
            var result = _xxxInfoService.GetLatestXXXInfoByCustomerId(int customerId);
            
            var s = JsonConvert.SerializeObject(result, Formatting.Indented,
                           new JsonSerializerSettings
                           {
                               ReferenceLoopHandling = ReferenceLoopHandling.Ignore,
                               PreserveReferencesHandling = PreserveReferencesHandling.None,
                           }).Trim();

            return Json(s);

        }

and on customer related parts I already used [JsonIgnore].

and the weird part I get this error once in a while then I need to rebuild and it works fine.

Any ideas how can I solve this issue?

Try creating a model for your data to serialize using the same property names, use automapper or just copy the properties over prior to serialization.   Looks like you're trying to serialize an entity to json!