Just realize one problem with LINQ to SQL

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.

When you have your ASP.NET session state stored in SQL Server, when you put any instance of your LINQ to SQL object into the session, you will hit by the about stated error.

I am still working on a fix for this. Will post the solution here once I found it.