Assembly: System.Web (in system.web.dll)
Return ValueAn object that contains the current view state of the control; otherwise, if there is no view state associated with the control, a null reference (Nothing in Visual Basic).
The SaveViewState method is used primarily by control developers.
View state is the cumulative values of the properties for a server control. These values are placed automatically in the ViewState property for the server control, which is an instance of the StateBag class. The ViewState property value is then persisted to a string object after the save state stage of the life cycle for the server control. 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 method and modifying the ViewState property for your server control. For more information, see ASP.NET State Management.