Each control on a Web Forms page, including the page itself, has a ViewState property that it inherits from the base Control class. View state is used by the ASP.NET page framework to automatically save the values of the page and of each control just prior to rendering to the page. When the page is posted, one of the first tasks performed by page processing is to restore view state.
You can use the ViewState property to save your values independent of control state between round trips to the server. The ViewState property is stored in the page in a hidden form field
