ASP.NET View State

ASP.NET view state is the technique used by an ASP.NET Web page to persist changes to the state of a Web Form across postbacks.

Events in the Page Life Cycle

View State and Dynamically Added Controls

Since the view state only persists changed control state across postbacks, and not the actual controls themselves, dynamically added controls must be added to the ASP.NET Web page, on both the initial visit as well as all subsequent postbacks. The view state for these dynamically added controls is automatically saved in the save view state stage. The best time to add these controls is during the initialization stage of the page life cycle, which occurs before the load view state stage.

MSDN: ASP.NET View State