Problem with a DataRow in Session

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sdettmers - 22 Jul 2005 16:42 GMT

Hi,

Database: SQL Server
Session: SQL Server
Language: C#
Application: ASP.Net

I have created a login page which attempts to retrieve the users record
from the database and I store the validated users DataRow into Session
which is in SQLServer. I have listed the error below for you to
review. I
can successfully store a DataRow on other pages. I don't understand
why it will work for one page and not the other.

The Error:

Unable to serialize the session state. Please note that
non-serializable objects or MarshalByRef objects are not permitted when
session state mode is 'StateServer' or 'SQLServer'.
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. Please note that non-serializable objects or
MarshalByRef objects are not permitted when session state mode is
'StateServer' or 'SQLServer'.

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: The type System.Xml.XmlBoundElement in
Assembly System.Data, Version=1.0.5000.0, Culture=neutral,
PublicKeyToken=b77a5c561934e089 is not marked as serializable.]

System.Runtime.Serialization.FormatterServices.InternalGetSerializableMembers(RuntimeType
type, Boolean excludeNonSerializable) +868

System.Runtime.Serialization.FormatterServices.GetSerializableMembers(Type
type, StreamingContext context) +300

System.Runtime.Serialization.Formatters.Binary.WriteObjectInfo.InitMemberInfo()
+103

System.Runtime.Serialization.Formatters.Binary.WriteObjectInfo.InitSerialize(Type
objectType, ISurrogateSelector surrogateSelector, StreamingContext
context, SerObjectInfoInit serObjectInfoInit, IFormatterConverter
converter) +362

System.Runtime.Serialization.Formatters.Binary.WriteObjectInfo.Serialize(Type
objectType, ISurrogateSelector surrogateSelector, StreamingContext
context, SerObjectInfoInit serObjectInfoInit, IFormatterConverter
converter) +48

System.Runtime.Serialization.Formatters.Binary.ObjectWriter.Write(WriteObjectInfo
objectInfo, NameInfo memberNameInfo, NameInfo typeNameInfo) +601

System.Runtime.Serialization.Formatters.Binary.ObjectWriter.Serialize(Object
graph, Header[] inHeaders, __BinaryWriter serWriter, Boolean fCheck)
+738

System.Runtime.Serialization.Formatters.Binary.BinaryFormatter.Serialize(Stream
serializationStream, Object graph, Header[] headers, Boolean fCheck)
+136
System.Web.Util.AltSerialization.WriteValueToStream(Object value,
BinaryWriter writer) +1621

[HttpException (0x80004005): Unable to serialize the session state.
Please note that non-serializable objects or MarshalByRef objects are
not permitted when session state mode is 'StateServer' or 'SQLServer'.]
System.Web.Util.AltSerialization.WriteValueToStream(Object value,
BinaryWriter writer) +1710
System.Web.SessionState.SessionDictionary.Serialize(BinaryWriter
writer) +148

System.Web.SessionState.StateClientManager.Serialize(SessionStateItem
item, Stream stream) +146

System.Web.SessionState.SqlStateClientManager.System.Web.SessionState.IStateClientManager.Set(String
id, SessionStateItem item, Boolean inStorage) +126
System.Web.SessionState.SessionStateModule.OnReleaseState(Object
source, EventArgs eventArgs) +465

System.Web.SyncEventExecutionStep.System.Web.HttpApplication+IExecutionStep.Execute()
+60
System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean&
completedSynchronously) +87

Version Information: Microsoft .NET Framework Version:1.1.4322.2032;
ASP.NET Version:1.1.4322.2032

Reply to this Message

Brock Allen - 22 Jul 2005 17:05 GMT

For objects to be stored in the SqlSever Session State mechanism, they need
to be able to be serialized. This typically means adding the [Serializable]
attribute to the class. It's essentially a permission slip to let the runtime
take all of the object's state and save it elsewhere (like a binary stream,
which might live in a file or in a database). The DataRow is not marked with
that attribute, thus it hasn't granted permission. IIRC, the DataTable and
DataSet are Serialazible, but those are fairly heavy weight objects to shove
into Session in your database. Consider storing your data in a more light-weight
mannger, perhaps as an array or ArrayList.

-Brock
DevelopMentor
http://staff.develop.com/ballen

> Hi,
>
[quoted text clipped - 92 lines]
> Version Information: Microsoft .NET Framework Version:1.1.4322.2032;
> ASP.NET Version:1.1.4322.2032

Reply to this Message

sdettmers - 22 Jul 2005 20:00 GMT

Brock

Thanks for the reply, I appreciate the help. I noticed that on the
microsoft web site they show the DataRow as a Serializable class. I
have posted the link below.

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/cpref/html/frlr
fsystemdatadatarowclasstopic.asp

Reply to this Message

Brock Allen - 22 Jul 2005 20:42 GMT

Interesting. I was looking at the 2.0 docs and had looked at the 2.0 version
of System.Data.dll, where it is not serializable.

-Brock
DevelopMentor
http://staff.develop.com/ballen

> Brock
>
[quoted text clipped - 4 lines]
> http://msdn.microsoft.com/library/default.asp?url=/library/en-us/cpref
> /html/frlrfsystemdatadatarowclasstopic.asp

Reply to this Message

Karl Seguin - 22 Jul 2005 17:09 GMT

While the DataRow is marked as serializable, it's Element property isn't.
It might have worked on some pages because this property was null, and not
on login because it isn't. Since Element property is only used internally,
my guess is that the difference between the two is in how it was created.

You could always use the datarow.ItemArray to get an array of objects...or
map the datarow to a custom User class

Karl

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> Hi,
>
[quoted text clipped - 91 lines]
> Version Information: Microsoft .NET Framework Version:1.1.4322.2032;
> ASP.NET Version:1.1.4322.2032

Reply to this Message

sdettmers - 22 Jul 2005 20:14 GMT

Karl,

I think you are on to something. On the pages where successfully
storing the DataRow I get the object from SQL but on the login page I
create a dummy DataRow incase the user record was not found in the
database. This was to avoid returning null on the call. I will have
to come up with a new way of handling the null return or create DTO
objects to store the data in Session.

Thanks for your help

Reply to this Message

Problem with a DataRow in Session

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