AjaxControlToolkit.PopupControlExtender.OnLoad C# (CSharp) Method

        protected override void OnLoad(EventArgs e)
        {
            base.OnLoad(e);

            // Attach the Page.PreRender event - Make sure we hook up only once
            if(_pagePreRenderHandler == null) {
                _pagePreRenderHandler = new EventHandler(Page_PreRender);
                Page.PreRender += _pagePreRenderHandler;
            }
        }