Assembly: System.Web.Services (in system.web.services.dll)
In a derived class, the ServiceDescriptionFormatExtension class allows users to define extensibility elements in addition to those defined in the Web Services Description Language (WSDL) specification. Extensibility elements can be added to a ServiceDescription at any of several levels within the class hierarchy. Thus many classes derived from the DocumentableItem class (including the ServiceDescription class) have an Extensions property, which returns a ServiceDescriptionFormatExtensionCollection.
Windows 98, Windows Server 2000 SP4, Windows Millennium Edition, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter EditionThe Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.