A MenuAdapter modifies the markup or behavior of a Menu control for a specific browser or class of browsers, or acts as a filter on some capability.
By default, the MenuItem objects in the Menu control are rendered as hyperlinks to accommodate menu navigation. The Menu class maintains state by implementing the IPostBackEventHandler interface so that it can respond to and raise specific events during postback. You can extend the MenuAdapter class to further customize rendering or behavior of the Menu control.
The initial request for an adapter causes the .NET Framework to search for a mapped adapter for the control, given the characteristics of the requesting browser. The HttpBrowserCapabilities class uses browser definition files to identify the characteristics of the client browser and to map the adapter to the browser type.
For more information about adaptive rendering in ASP.NET, see Architectural Overview of Adaptive Control Behavior.