asp.net Gridview分页保存选项

代码如下:
#region //'Revision: 1.00 Created Date: 2013/08/02 Created ID: Una [#1300071]增加多選框
        /// <summary>
        /// Session獲取多選框值
        /// </summary>
        private void RememberOldValues()
        {
            ArrayList categoryIDList = new ArrayList();
            string index = "";
            foreach (GridViewRow row in gridView.Rows)
            {
                index = (string)gridView.DataKeys[row.RowIndex].Value;
                bool result = ((CheckBox)row.FindControl("DeleteThis")).Checked;

                // Check in the Session
                if (Session["id"] != null)
                    categoryIDList = (ArrayList)Session["id"];
                if (result)
                {
                    if (!categoryIDList.Contains(index))
                        categoryIDList.Add(index);
                }
                else
                    categoryIDList.Remove(index);
            }
            if (categoryIDList != null && categoryIDList.Count > 0)
                Session["id"] = categoryIDList;
        }

        /// <summary>
        /// Session分頁時之前多選框為true
        /// </summary>
        private void RePopulateValues()