Using this member is the simplest way to save and retrieve view-state values for a control or a page.
If an item is not already stored in the StateBag object when you set this property, its key/value pair is added to the collection. If you set this property to null before the TrackViewState method is called on an item, it is removed from the StateBag object. Otherwise, when you set this property to null the key is saved to allow tracking of the item's view state.
// Add property values to view state with set; // retrieve them from view state with get. public String Text
object o = ViewState["Text"];
return (o == null)? String.Empty : (string)o;
ViewState["Text"] = value;
Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)