Provides a base class for all strongly typed collections that manage IStateManager objects.
Assembly: System.Web (in System.Web.dll)
The class is the base class for all strongly typed collections that store IStateManager elements, including DataControlFieldCollection, ParameterCollection, StyleCollection, TreeNodeBindingCollection, and others. The collection manages its own state as well as the state of the elements it contains. Therefore, a call to SaveViewState saves the state of the collection and the state of all the elements currently contained by the collection.
The most important methods to consider when deriving from the class are CreateKnownType, GetKnownTypes, OnValidate, SetDirty, and SetDirtyObject. The CreateKnownType and GetKnownTypes methods are used to store an index in view state for the type of a contained element. Storing an index rather than a fully qualified type name improves performance. The OnValidate method is called whenever elements of the collection are manipulated, and validates the elements according to business rules. Currently, the implementation of the OnValidate method prohibits a null reference (Nothing in Visual Basic) objects from being stored in the collection; however, you can override this method to define your own validation behavior in a derived type. The SetDirty method forces the entire collection to be serialized to view state, rather than just serializing changes made to state since the last time it was loaded. The SetDirtyObject method is an abstract method you can implement to perform this same behavior at the element level.
stores assembly-qualified type names of the collection items in view state. A site visitor could decode the view state and retrieve the type name. If this scenario creates a security concern in your Web site, you can manually encrypt the type name before placing it in the view state.
The following code example demonstrates how to derive a strongly typed collection class from to contain IStateManager objects. In this example, the CycleCollection is derived to contain instances of the abstract Cycle class, which can be either Bicycle or Tricycle objects. The Cycle class implements the IStateManager interface because it stores the value of the CycleColor property in view state.
Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98
The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.