An object that contains the adapter view state information as a System.Web.UI.StateBag.
When an adapter needs to maintain its own view state information, it can override the ControlAdapter.SaveAdapterViewState and ControlAdapter.LoadAdapterViewState(object) methods.
An adapter needs to maintain view state information when there is data that must be maintained across requests, independent from the associated view state of the control. For example, a grid control on desktop computer browsers might render as a single view of rows and columns of values. On other browsers, it might split its rendering into multiple separate views, such as a list of rows and details of a single row. The adapter would need to maintain the data for the views that are not currently active in view state.
The ControlAdapter.SaveAdapterViewState method is called immediately before the System.Web.UI.Control.SaveViewState method in the SaveState lifecycle stage. The adapter view state is separate and in addition to the view state of the control.