The VirtualFileBase abstract class provides the common methods and properties shared between the VirtualFile and VirtualDirectory objects. Implementations of these classes provide the ASP.NET runtime with access to files and paths used for compilation. For more information on using virtual files and paths, see the VirtualPathProvider class.
Notes to Inheritors:
When you inherit from the VirtualFileBase class, you must override the IsDirectory property to indicate whether the derived object is a virtual directory or a virtual file. If you derive from either the VirtualFile or the VirtualDirectory class, the IsDirectory property is already set.