突然發現我的基礎太爛了

        GridView BindingControl
        {
            get
            {
                const string SessionName = "{79c651df-45ef-4893-a0e3-f320eac9a8c6}";
                object objControl = Page.Session[SessionName];
                if (objControl == null)
                {
                    foreach (Control ctl in Page.Controls)
                    {
                        Page.Session[SessionName] = GetControl(ctl);
                        return (GridView)Page.Session[SessionName];
                    }
                }
                return (GridView)objControl;
            }
            set { Page.Session["{79c651df-45ef-4893-a0e3-f320eac9a8c6}"] = value; }
        }

        GridView GetControl(Control ctlContainer)
        {
            if (ctlContainer.GetType().Name == "GridView" && ctlContainer.ID == BindingControlID)
            {
                return (GridView)ctlContainer;
            }
            if (ctlContainer.Controls.Count > 0)
            {
                foreach (Control ctl in ctlContainer.Controls)
                {
                    GetControl(ctl);
                }
            }
            return null;
        }

如果 頁面存在 GridView1, BindingControl = ？

頁面有 GridView1，能找到，但BindingControl始終爲null，爲什麼？