Additional State Management Considerations
You cannot store state information in either static variables or member variables between requests. Static variables are shared across all requests to that page, so you never know in which request the value of the variable was set. Member variables lose their value, because the page is discarded after every response and rebuilt for every request.
Controlling Session State | Supporting View State | Creating ASP.NET Mobile Web Applications | Application Developer's Guide | Developing Mobile Web Applications | ASP.NET State Management | LoadPrivateViewState | SavePrivateViewState