Classes used for Web Forms controls

The System.Web.UI.Control class: Each Web Forms control is a class that inherits from the System.Web.UI.Control class directly or indirectly. The System.Web.UI.Control class defines all the properties, events, and methods that are common to all the Web Forms controls. We need to inherit our control from this class in the following cases: -
•    When our control does not have a user interface
•    When our control includes that render their own user interface