public static DataTable GetAllCategory()
        {
            string sql = string.Format(@"SELECT categoryName FROM Categories");

            return(DataAccessLayer.Retreiving(sql));
        }
        public static string GetCategoryID(string CategoryName)
        {
            string sql = string.Format(@"SELECT categoryID FROM Categories WHERE categoryName = '{0}'", CategoryName);

            return(DataAccessLayer.Retreiving(sql).Rows[0][0].ToString());
        }