Saves the changes to the control view state since the time the page was posted back to the server.
Assembly: System.Web (in System.Web.dll)
The 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 server control's ViewState property, which is an instance of the StateBag class. The ViewState 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 ASP.NET Page Life Cycle Overview.
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 method and modifying the ViewState property for your server control. For more information, see Developing Custom ASP.NET Server Controls and ASP.NET State Management Overview.