Question

What I want to achieve is something like this below, which Visual Studio complains about and I don’t know how to achieve it:

public abstract class My_BaseControl<T> : T, IRightBasedUsability
        where T : System.Web.UI.WebControls.WebControl 
{

    // Some methods that I want to have for all 
    //the extended asp.net controls along my application
    //which implements IRightBasedUsability

}

Answer 1

Perhaps c# extension methods are in this case a way to solve your problem.

@see http://msdn.microsoft.com/en-us/library/bb383977.aspx

Eric De Carufel wrote some interesting articles about extension methods and how to manage their scope:
http://blog.decarufel.net/2009/02/extension-methods-series-managing-scope.html