how to make usercontorl event available in a single cs file

i read several articles about consuming usercontrol event in pages. but my case is a little different... i create a new cs file(just cs file ,no aspx file)  as a template class for other pages to inherit. in this class,i add two usercontorls ,one for page head,the other for page foot...so each page inherit this template class would automaticallly get page head and page foot..there is a dropdownlist in the page foot usercontrol...my issue is : the OnSelectedIndexChanged event of that dropdownlist cannot fire. the following is the code snippet:

abstract public class FriendsFooter : System.Web.UI.UserControl   // this is the class i wrote for usercontrol to get its EventHandler ,because i don't know 
    {                                   ...