AjaxControlToolkit.ModalPopupExtender.OnPreRender C# (CSharp) Method

        protected override void OnPreRender(EventArgs e)
        {
            // If Show() or Hide() were called during the request, change the visibility now
            if(_show.HasValue)
                ChangeVisibility(_show.Value);

            ResolveControlIDs(_onShown);
            ResolveControlIDs(_onHidden);
            ResolveControlIDs(_onShowing);
            ResolveControlIDs(_onHiding);

            base.OnPreRender(e);
        }