I can't tell from your description if your talking about an application or a web page. Despite Microsoft's attempts to plaster over the differences and pretend building an application is the same as building a web application, there are significant differences.
As for your question, your interface items have to be in some sort of container. And most Microsoft containers have a find method of some sort that will go from an objects name to the object. In ASP.NET it is FindControl.
Jay