How to implement interface's method in aspx?

[yp.yean]

Hello,

I have a ASP.NET control with interface called "INamingRule". The
interface structure as follows:

public interface INamingRule
{
string GenerateName ();
}

Now I want to let ASP.NET application developers to develop their own
naming rule by implement GenerateName() method in aspx (web
application). I have no idea how to implement this feature in my server
control. Could somebody can give me the suggestion?

Thank you for any suggestion.