Unable to serialize the session state

Question

When putting my application on a web server and trying to 'log in' I get the following error:

Server Error in '/' Application.
Unable to serialize the session state. In 'StateServer' and 'SQLServer' mode, ASP.NET will serialize the session state objects, and as a result non-serializable objects or MarshalByRef objects are not permitted. The same restriction applies if similar serialization is done by the custom session state store in 'Custom' mode.
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.Web.HttpException: Unable to serialize the session state. In 'StateServer' and 'SQLServer' mode, ASP.NET will serialize the session state objects, and as a result non-serializable objects or MarshalByRef objects are not permitted. The same restriction applies if similar serialization is done by the custom session state store in 'Custom' mode.

Source Error:

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.

Stack Trace:

[SerializationException: Type 'Gebruiker' in Assembly 'App_Code.qzuhycmn, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null' is not marked as serializable.]
   System.Runtime.Serialization.FormatterServices.InternalGetSerializableMembers(RuntimeType type) +9452985
   System.Runtime.Serialization.FormatterServices.GetSerializableMembers(Type type, StreamingContext context) +247
   System.Runtime.Serialization.Formatters.Binary.WriteObjectInfo.InitMemberInfo() +160
   System.Runtime.Serialization.Formatters.Binary.WriteObjectInfo.InitSerialize(Object obj, ISurrogateSelector surrogateSelector, StreamingContext context, SerObjectInfoInit serObjectInfoInit, IFormatterConverter converter, ObjectWriter objectWriter, SerializationBinder binder) +218
   System.Runtime.Serialization.Formatters.Binary.WriteObjectInfo.Serialize(Object obj, ISurrogateSelector surrogateSelector, StreamingContext context, SerObjectInfoInit serObjectInfoInit, IFormatterConverter converter, ObjectWriter objectWriter, SerializationBinder binder) +54
   System.Runtime.Serialization.Formatters.Binary.ObjectWriter.Serialize(Object graph, Header[] inHeaders, __BinaryWriter serWriter, Boolean fCheck) +542
   System.Runtime.Serialization.Formatters.Binary.BinaryFormatter.Serialize(Stream serializationStream, Object graph, Header[] headers, Boolean fCheck) +133
   System.Web.Util.AltSerialization.WriteValueToStream(Object value, BinaryWriter writer) +1708

[HttpException (0x80004005): Unable to serialize the session state. In 'StateServer' and 'SQLServer' mode, ASP.NET will serialize the session state objects, and as a result non-serializable objects or MarshalByRef objects are not permitted. The same restriction applies if similar serialization is done by the custom session state store in 'Custom' mode.]
   System.Web.Util.AltSerialization.WriteValueToStream(Object value, BinaryWriter writer) +1793
   System.Web.SessionState.SessionStateItemCollection.WriteValueToStreamWithAssert(Object value, BinaryWriter writer) +34
   System.Web.SessionState.SessionStateItemCollection.Serialize(BinaryWriter writer) +638
   System.Web.SessionState.SessionStateUtility.Serialize(SessionStateStoreData item, Stream stream) +244
   System.Web.SessionState.SessionStateUtility.SerializeStoreData(SessionStateStoreData item, Int32 initialStreamSize, Byte[]& buf, Int32& length, Boolean compressionEnabled) +67
   System.Web.SessionState.OutOfProcSessionStateStore.SetAndReleaseItemExclusive(HttpContext context, String id, SessionStateStoreData item, Object lockId, Boolean newItem) +114
   System.Web.SessionState.SessionStateModule.OnReleaseState(Object source, EventArgs eventArgs) +807
   System.Web.SessionState.SessionStateModule.OnEndRequest(Object source, EventArgs eventArgs) +184
   System.Web.SyncEventExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +148
   System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +75


Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.0.30319.1 

The only thing I do there with Sessions is this:

• Session["Rechten"] = "GlobaalAdmin"; (example)
• Session["gebruikerid"] = txtID.Text; (the ID they log in with)
• And redirect them to another page: Response.Redirect("LoggedIn.aspx",true);
• http://pastebin.com/jZprwA8m (Putting the gebruiker into a session)

There have been multiple topics about this problem but none of them seem to have helped me. Everything works locally, but online it doesn't.

Whim

It looks like an instance of a Gebruiker object is being serialized somewhere along the way (and it probably wasn't tagged with the [Serializable] attribute). – Shank

The reason is stated explicitly in the stack trace you posted: [SerializationException: Type 'Gebruiker' in Assembly 'App_Code.qzuhycmn, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null' is not marked as serializable.]. Are you really sure you only put strings in the session, like you say you do? – Bethought

pastebin.com/jZprwA8m Is the only time I make on "object" of gebruiker. – Whim

Answer 1

Can we see the "Gebruiker" class? There error seems straightforward enough. Gebruiker is not attributed as being Serializable therefore it can't be placed in Session for StateServer and SQLServer modes.

EDIT:

After looking at the code you linked in, yes, it's probably because the class isn't serializable. The LINQ generated class should be a partial class so you can implement your own partial class that marks it as Serializable and the sessionstate requirements will be met then.

[Serializable()]
public partial class Gebruiker { //Lots of stuff }

EDIT 2:

Thomas, your Gebruiker class probably has a definition that looks like this right now (or something similar)

namespace XYZ
{
   public partial class Gebruiker
}

Just create another class file that has the same namespace and define the class with the Serializable attribute

namespace XYZ
{
  [Serializable()]
  public partial class Gebruiker{}
}

That's all you should need in this file. This way, the serializable attribute won't be overwritten when the LINQ generated Gebruiker class gets created.

Clausen

@John: I posted a link to pastebin with the class in it. – Whim

@Thomas: that's not the class. That's you putting an instance of the class into Session. – Fenugreek

@John that's the link in my initial question, but in my comment to the answer I linked to the actual class: pastebin.com/nww2enQ5 – Whim

@Khepri: So I just have to add [Serializable()] in front of the class "Gebruiker"? Or do I have to create a new class? Thanks for the help so far :) – Whim

If your class isn't always regenerated then yes, you can just add the [Serializable()] attribute. But if it's an auto-generated class (which it sounds like it is), then you'll have to create another partial class and implement the attribute so that change doesn't get overwritten all the time. – Clausen

using a partial to apply a class attribute is genious. Thanks! – Redound

Adding [Serializable()] fixed my issue, Thanks! – Revamp

Answer 2

The regular session is simply stored in memory, but when you are working in a load-balanced environment you cannot rely on the same server handling postbacks why the session must be stored in a shared session mechanism primarily SQL Server and StateServer.

This can be configured in machine.config or somewhere deeper than the app web.config why might not be aware of such a change but it could explain your sudden exception when deploying to the internet.

As mentioned in another answer and in the comments the problem would then arise when the session object is not [Serializable]; while you are working in regular session the object is not serialized but just stored in server memory, but going online introduces different session mechanisms and the need for the objects to be serializable.

Dysthymia

I forgot to add that I put an object of the current "Gebruiker" into a session. pastebin.com/jZprwA8m I'm guessing this is the problem? – Whim

Ok, but you should still be able to mark it as Serializable since it will be generated as a partial class (as far as I remember) so in some other file you could put [Serializable] public partial class Gebruiker {} – Dysthymia

Answer 3

Based on the code you posted: that class is generated as partial, so all you need to do is add another partial definition like this (in the same namespace as the generated partial class, of course):

[Serializable]
public partial class Gebruiker {}

Bethought

Answer 4

There is another solution, While inheriting a non-serializable class also implment ISerlializable interface GetObjectData method. Inherited class should also be marked as [Serializable].

Stricklin

Answer 5

Some times you have to check below property in your web.config

<sessionState mode="InProc" ........../>

Womenfolk

Answer 6

If you come across this error message on SharePoint 2013, don't forget to run the following PowerShell cmdlet:

Enable-SPSessionStateService -DefaultProvision

This error message is new in SP2013; see this question for SP2010: Session state can only be used when enableSessionState is set to true either in a configuration

Cameroncameroon

Answer 7

In my case, I was trying to serialize the non-serialized object that is HttpResponse. So if provided solutions won't work, you can go through solution of unable to serialize session state article.

Hope it help others!

Egwan

Answer 8

If SessionState mode = "SQLServer" then you have to use [Serializable()] public partial class Gebruiker .

otherwise you have to change your SessionState mode to "Inproc" Example :

Lollis