It seems to me that a Context class is a control console that its object can invoke any included functions, such as Datacontext and DoaminContext in WCF Ria service. Do I understand this concept correctly? If so, in what circumstances do I need to create a context class in my own class hierarchy?
Beside DataContext, what other well-known Context classes do the .net framework have?
You can think about the context as a wrapper for related "things" such as HttpContext, DbContext, ObjectContext. i.e.: HttpContext contains any information you can reach for HTTP related operations.
DbContext contains the methods and properties for database communication. Likewise ObjectContext.
I would say it's a placeholder or container of related things for something.