This class exposes the method RegisterObjectCreationCallback( ), which specifies a delegate that manufactures instances of a managed type. Use this to build managed types that extend unmanaged types. Since a managed type cannot directly inherit from an unmanaged type, the managed type needs to aggregate an instance of the unmanaged type. The delegate that you register with RegisterObjectCreationCallback( ) takes care of creating the unmanaged type.

public sealed class ExtensibleClassFactory {
// Public Static Methods
   public static void RegisterObjectCreationCallback(ObjectCreationDelegate callback);
}