Most of the web applications require maintaining session state with the help of various mechanisms. While working with Silverlight, we may need Add or Get data from ASP.Net session.
As the Silverlight works in client’s environment, it does not have direct access to ASP.Net session object. The only way we can retrieve the information from Session is through Web Service.
I have published an article in CodeProject with source code too at the below link: http://www.codeproject.com/KB/silverlight/SilverlightASPNetSessions.aspx