asp.net - Viewstate move session generate an error as 'The state information is invalid for this page and might be corrupted. ' -

i have created web page rad grid. within provide facility filtering ,shorting, grouping , paging . because of performance issue have tried move viewsatate session. there have set enable viewsate false in webpage , added bellow code page.

    protected override object loadpagestatefrompersistencemedium()     {         return session["viewstate-" + request.url.absolutepath];      }     protected override void savepagestatetopersistencemedium(object state)     {         session["viewstate-" + request.url.absolutepath] = state;          clientscript.registerhiddenfield("__viewstate", "");     } 

but when thing on rad grid generate bellow error

the state information invalid page , might corrupted.

if using asp.net 2.0 or higher, microsoft has built-in functionality viewstate in session. should use maximum compatibility.

just put in .cs file

protected override pagestatepersister pagestatepersister {     {                      return new system.web.ui.sessionpagestatepersister(this);   } } 

link @ http://msdn.microsoft.com/en-sg/library/system.web.ui.sessionpagestatepersister.aspx