Page and control developers do not use the System.Web.UI.ControlSkinDelegate, System.Web.UI.ControlSkin, or System.Web.UI.PageTheme classes directly. These classes are used internally by the ASP.NET page framework to apply server-side properties and cascading style sheet definitions that are defined in ASP.NET themes and control skin files to specific types of controls.

System.Web.UI.ControlSkin objects represent a named skin or default skin of a System.Web.UI.Control control at run time and design time. ASP.NET builds System.Web.UI.PageTheme, System.Web.UI.ControlSkin and System.Web.UI.ControlSkinDelegate objects to apply the style elements defined in themes and control skin files to ASP.NET Web pages and controls.

For more information about themes and control skins, see Introduction to ASP.NET Themes.