System.Web.UI Namespace

Contains the HTML cascading-style sheets ( CSS ) inline style attributes for a specified HTML server control. This class cannot be inherited.

Any style declared for a particular HTML server control is added to the collection when the containing Web Forms page is parsed. It automatically parses and exposes CSS properties through a dictionary pattern API. You can manipulate any CSS property on a server control through the Style property. Simply use the CSS property's key and value in the indexed collection.

The following example demonstrates iterating through an HTML server control's CSSStyleCollection object and rendering all the keys and their values to a Web Forms page.

ASP.NET Server Controls and CSS Styles   Style