Default.aspx.cs

    public class BasePage : Page
    {
        public BasePage()
        {
            ObjectFactory.BuildUp(this);
        }
    }

    public partial class _Default : BasePage   // new base class
    {
        public IWhateverService WhateverService { private get; set; }
        public ISomethingElse SomethingElseService { private get; set; }

        protected void Page_Load(object sender, EventArgs e)
        {
            Response.Write(WhateverService.HelloWorld());
            Response.Write(SomethingElseService.HelloWorld2());
        }
    }