ASP.NET AJAX Networking and Web Services

Re: Circular Reference with Complex Type

KaziManzurRashid — Sat, 13 Oct 2007 23:48:08 GMT

To deal with Circular reference you have to write your own custom JavaScriptConverter, checkout the Serialize incompatible types of this article:
http://dotnetslackers.com/columns/ajax/ASPNETAjaxWebService.aspx

Re: Circular Reference with Complex Type

dear.saxena — Fri, 12 Oct 2007 09:44:26 GMT

Hi Neil,

I am facing the same problem if you have any solution please let me know.

Thanks Saurabh Saxena

Re: Circular Reference with Complex Type

NJW — Fri, 07 Apr 2006 17:20:36 GMT

I am encountering the same error as is described above.

I understand that there will be issues when the object graph has a circular reference in it, however I am encountering this issue when I simply attempt to return a System.Data.DataTable comprised of columns with simple data types.

What I'm currently attempting to do is call the 'getTableFromService' JavaScript function and get a DataTable back from the Web Service. I've included both the Service and the JavaScript.

My error handling function output is also included at the bottom.

Any help you can provide would be greatly appreciated.

Thanks,

neil

Imports System
Imports System.Data
Imports System.Web.Services

Namespace Services

    <WebService(Namespace:="http://tempuri.org/")> _
    <WebServiceBinding(ConformsTo:=WsiProfiles.BasicProfile1_1)> _
    Public Class SampleDataTable
        Inherits System.Web.Services.WebService

        <WebMethod()> Public Function GetTable() As System.Data.DataTable
            Dim dtResults As New System.Data.DataTable
            Dim drRow As System.Data.DataRow = Nothing
            dtResults.Columns.Add(New System.Data.DataColumn("ID", GetType(Integer)))
            dtResults.Columns.Add(New System.Data.DataColumn("Digit", GetType(Integer)))

            drRow = dtResults.NewRow()
            drRow.Item("ID") = 1
            drRow.Item("Digit") = 1

            dtResults.Rows.Add(drRow)

            Return dtResults
        End Function

    End Class

End Namespace

function getTableFromService(){
    Services.SampleDataTable.GetTable(onSuccess, onTimeout, onError); 
}function onSuccess( Results ){
    //success}function onTimeout( Results ){
    //timeout}function onError( Results ){
    alert('Error Type:\n' + Results.get_exceptionType() + '\n\nError:\n' + Results.get_message() + '\n\nStack Trace:\n' + Results.get_stackTrace());}

---------------------------
Microsoft Internet Explorer
---------------------------
Error Type:
System.InvalidOperationException

Error:
A circular reference was detected while serializing an object of type 'System.Reflection.Module'.

Stack Trace:
   at Microsoft.Web.Script.Serialization.JavaScriptObjectSerializer.SerializeValueInternal(Object o)

   at Microsoft.Web.Script.Serialization.JavaScriptObjectSerializer.SerializeValue(Object o)

   at Microsoft.Web.Script.Serialization.JavaScriptObjectSerializer.SerializeCustomObject(Object o)

   at Microsoft.Web.Script.Serialization.JavaScriptObjectSerializer.SerializeValueInternal(Object o)

   at Microsoft.Web.Script.Serialization.JavaScriptObjectSerializer.SerializeValue(Object o)

   at Microsoft.Web.Script.Serialization.JavaScriptObjectSerializer.SerializeCustomObject(Object o)

   at Microsoft.Web.Script.Serialization.JavaScriptObjectSerializer.SerializeValueInternal(Object o)

   at Microsoft.Web.Script.Serialization.JavaScriptObjectSerializer.SerializeValue(Object o)

   at Microsoft.Web.Script.Serialization.JavaScriptObjectSerializer.SerializeCustomObject(Object o)

   at Microsoft.Web.Script.Serialization.JavaScriptObjectSerializer.SerializeValueInternal(Object o)

   at Microsoft.Web.Script.Serialization.JavaScriptObjectSerializer.SerializeValue(Object o)

   at Microsoft.Web.Script.Serialization.JavaScriptObjectSerializer.SerializeCustomObject(Object o)

   at Microsoft.Web.Script.Serialization.JavaScriptObjectSerializer.SerializeValueInternal(Object o)

   at Microsoft.Web.Script.Serialization.JavaScriptObjectSerializer.SerializeValue(Object o)

   at Microsoft.Web.Script.Serialization.JavaScriptObjectSerializer.SerializeEnumerable(IEnumerable enumerable)

   at Microsoft.Web.Script.Serialization.JavaScriptObjectSerializer.SerializeValueInternal(Object o)

   at Microsoft.Web.Script.Serialization.JavaScriptObjectSerializer.SerializeValue(Object o)

   at Microsoft.Web.Script.Serialization.JavaScriptObjectSerializer.SerializeCustomObject(Object o)

   at Microsoft.Web.Script.Serialization.JavaScriptObjectSerializer.SerializeValueInternal(Object o)

   at Microsoft.Web.Script.Serialization.JavaScriptObjectSerializer.SerializeValue(Object o)

   at Microsoft.Web.Script.Serialization.JavaScriptObjectSerializer.Serialize(Object o, IJavaScriptSerializationContext context)

   at Microsoft.Web.Services.RestHandler.ProcessRequest(HttpContext context)
---------------------------
OK   
---------------------------

Re: Circular Reference with Complex Type

davidebb — Tue, 04 Apr 2006 19:57:31 GMT

There is no limit to the complexity of what can be returned, but the object graph cannot have a circular reference. However, I would expect the same limitation when calling it as a standard web service, which as I understand from you post works correctly. So there may be something else going on. Maybe you have some special serialization attributes that Atlas is not honoring correctly?

Circular Reference with Complex Type

pcoulter — Tue, 04 Apr 2006 16:33:53 GMT

I have created a webservice that returns a complex type. This is the xml that is returned from the webservice:

<NinjaRouteEntity xmlns="http://tempuri.org/">
<Entity NinjaRouteID="1" xmlns="">
    <AlwaysFetchToRegion>False</AlwaysFetchToRegion>
    <TimeFrameReturnsNewIfNotFound>True</TimeFrameReturnsNewIfNotFound>
    <AlwaysFetchFromRegion>False</AlwaysFetchFromRegion>
    <EntityCollectionReference PropertyName="PointCollectionViaNinjaRouteVector">
      <PointCollectionViaNinjaRouteVector>
        <Entities />
        <AllowRemove>False</AllowRemove>
        <AllowEdit>True</AllowEdit>
        <AllowNew>True</AllowNew>
      </PointCollectionViaNinjaRouteVector>
    </EntityCollectionReference>
    <ToRegionReturnsNewIfNotFound>True</ToRegionReturnsNewIfNotFound>
    <EntityReference PropertyName="TimeFrame" />
    <EntityReference PropertyName="FromRegion" />
    <IsNew>False</IsNew>
    <FromRegionReturnsNewIfNotFound>True</FromRegionReturnsNewIfNotFound>
    <AlwaysFetchNinjaRouteVector>False</AlwaysFetchNinjaRouteVector>
    <AlwaysFetchPointCollectionViaNinjaRouteVector>False</AlwaysFetchPointCollectionViaNinjaRouteVector>
    <EntityReference PropertyName="ToRegion" />
    <AlwaysFetchTimeFrame>False</AlwaysFetchTimeFrame>
    <AlwaysFetchSuggestedRouteCollectionViaNinjaSuggestedRoute>False</AlwaysFetchSuggestedRouteCollectionViaNinjaSuggestedRoute>
    <EntityCollectionReference PropertyName="SuggestedRouteCollectionViaNinjaSuggestedRoute">
      <SuggestedRouteCollectionViaNinjaSuggestedRoute>
        <Entities />
        <AllowRemove>False</AllowRemove>
        <AllowEdit>True</AllowEdit>
        <AllowNew>True</AllowNew>
      </SuggestedRouteCollectionViaNinjaSuggestedRoute>
    </EntityCollectionReference>
    <EntityCollectionReference PropertyName="NinjaSuggestedRoute">
      <NinjaSuggestedRoute>
        <Entities />
        <AllowRemove>False</AllowRemove>
        <AllowEdit>True</AllowEdit>
        <AllowNew>True</AllowNew>
      </NinjaSuggestedRoute>
    </EntityCollectionReference>
    <ObjectID>7ba4f8ed-08d5-47cb-9dcc-096725d03d69</ObjectID>
    <EntityCollectionReference PropertyName="NinjaRouteVector">
      <NinjaRouteVector>
        <Entities />
        <AllowRemove>False</AllowRemove>
        <AllowEdit>True</AllowEdit>
        <AllowNew>True</AllowNew>
      </NinjaRouteVector>
    </EntityCollectionReference>
    <AlwaysFetchNinjaSuggestedRoute>False</AlwaysFetchNinjaSuggestedRoute>
    <Fields>
      <NinjaRouteID>
        <CurrentValue>1</CurrentValue>
        <DbValue>1</DbValue>
        <IsChanged>False</IsChanged>
        <IsNull>False</IsNull>
      </NinjaRouteID>
      <Name>
        <CurrentValue>My Awesomer Route</CurrentValue>
        <DbValue>My Awesomer Route</DbValue>
        <IsChanged>False</IsChanged>
        <IsNull>False</IsNull>
      </Name>
      <Description>
        <CurrentValue>Go from here to there.</CurrentValue>
        <DbValue>Go from here to there.</DbValue>
        <IsChanged>False</IsChanged>
        <IsNull>False</IsNull>
      </Description>
      <CreatorID>
        <CurrentValue>4b4a743b-345f-4dd6-905a-bb59708491ed</CurrentValue>
        <DbValue>4b4a743b-345f-4dd6-905a-bb59708491ed</DbValue>
        <IsChanged>False</IsChanged>
        <IsNull>False</IsNull>
      </CreatorID>
      <DateCreated>
        <CurrentValue>2006-01-31T01:45:34.0000000-08:00</CurrentValue>
        <DbValue>2006-01-31T01:45:34.0000000-08:00</DbValue>
        <IsChanged>False</IsChanged>
        <IsNull>False</IsNull>
      </DateCreated>
      <FromRegionID>
        <CurrentValue>1</CurrentValue>
        <DbValue>1</DbValue>
        <IsChanged>False</IsChanged>
        <IsNull>False</IsNull>
      </FromRegionID>
      <ToRegionID>
        <CurrentValue>2</CurrentValue>
        <DbValue>2</DbValue>
        <IsChanged>False</IsChanged>
        <IsNull>False</IsNull>
      </ToRegionID>
      <TimeFrameID>
        <CurrentValue>2</CurrentValue>
        <DbValue>2</DbValue>
        <IsChanged>False</IsChanged>
        <IsNull>False</IsNull>
      </TimeFrameID>
    </Fields>
    <IsDirty>False</IsDirty>
    <EntityState>Fetched</EntityState>
    <SavedFieldSets />
</Entity>
</NinjaRouteEntity>

When I try to call it with Atlas, I see this error via Fiddler:

new Sys.Net.MethodRequestError("A circular reference was detected while serializing an object of type \'FlatlandMedia.NinjaRoutes.Dal.EntityClasses.NinjaRouteEntity\'."," at Microsoft.Web.Script.Serialization.JavaScriptObjectSerializer.SerializeValueInternal(Object o)\r\n at Microsoft.Web.Script.Serialization.JavaScriptObjectSerializer.SerializeValue(Object o)\r\n at Microsoft.Web.Script.Serialization.JavaScriptObjectSerializer.SerializeCustomObject(Object o)\r\n at Microsoft.Web.Script.Serialization.JavaScriptObjectSerializer.SerializeValueInternal(Object o)\r\n at Microsoft.Web.Script.Serialization.JavaScriptObjectSerializer.SerializeValue(Object o)\r\n at Microsoft.Web.Script.Serialization.JavaScriptObjectSerializer.SerializeEnumerable(IEnumerable enumerable)\r\n at Microsoft.Web.Script.Serialization.JavaScriptObjectSerializer.SerializeValueInternal(Object o)\r\n at Microsoft.Web.Script.Serialization.JavaScriptObjectSerializer.SerializeValue(Object o)\r\n at Microsoft.Web.Script.Serialization.JavaScriptObjectSerializer.SerializeCustomObject(Object o)\r\n at Microsoft.Web.Script.Serialization.JavaScriptObjectSerializer.SerializeValueInternal(Object o)\r\n at Microsoft.Web.Script.Serialization.JavaScriptObjectSerializer.SerializeValue(Object o)\r\n at Microsoft.Web.Services.RestHandler.ProcessRequest(HttpContext context)","System.InvalidOperationException")

Any way around this? Are there any guidelines as to how complex a type can be?

Thanks for any help on this.