Assembly: System.Web (in system.web.dll)
Return ValueThe object that contains the changes to the CheckBox view state; otherwise, if no view state is associated with the object, a null reference (Nothing in Visual Basic).
The SaveViewState method is used primarily by control developers.
View state is the accumulation of the values of a server control's properties. These values are automatically placed in the ViewState property for the server control, which is an instance of the StateBag class. This property's value is then persisted to a string object after the save-state stage of the server control's life cycle. For more information, see Introduction to the ASP.NET Page Life Cycle.
When view state is saved, this string object is returned to the client as a variable that is stored in a hidden HTML input element. When you author custom server controls, you can improve efficiency by overriding the SaveViewState and modifying the ViewState property for your server control. For more information, see Developing Custom ASP.NET Server Controls and ASP.NET State Management.