Ado.Net实现简易（省、市、县）三级联动查询，还附加Access数据

 private static readonly string accessConn = @"Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" + Directory.GetCurrentDirectory() + (@"\Areafull.accdb");

        /// <summary>
        /// 查询access数据，返回table
        /// </summary>
        /// <param name="sql">执行sql</param>
        /// <param name="parameters">查询参数</param>
        /// <returns></returns>
        public static DataTable ExecuteAccessDateTable(string sql, params SqlParameter[] parameters)
        {
            using (OleDbConnection cnn = new OleDbConnection(accessConn))
            {
                cnn.Open();
                using (OleDbCommand cmd = cnn.CreateCommand())
                {
                    cmd.CommandText = sql;
                    cmd.Parameters.AddRange(parameters);
                    OleDbDataReader apter = cmd.ExecuteReader();
                    DataTable dt = new DataTable();
                    dt.Load(apter);
                    return dt;
                }
            }
        }

       /// <summary>
       /// 初始化加载省数据
       /// </summary>
       /// <param name="sender"></param>
       /// <param name="e"></param>
        private void Window_Loaded(object sender, RoutedEventArgs e)
        {
            DataTable table = SqlHelper.ExecuteAccessDateTable("select * from areafull where AreaPid=‘0‘");
            SlB.ItemsSource = GetAreas(table);//省份绑定
        }

        /// <summary>
        /// 省数据选择
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void SlB_SelectionChanged(object sender, SelectionChangedEventArgs e)
        {
            Area areaRow = (Area)SlB.SelectedItem;
            DataTable table = SqlHelper.ExecuteDateTable("select * from areafull where AreaPid=@AreaPid", new SqlParameter("@AreaPid", areaRow.AreaId));
            SJBX.ItemsSource = GetAreas(table);
        }

        /// <summary>
        /// 市级数据选择
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void SJBX_SelectionChanged(object sender, SelectionChangedEventArgs e)
        {
            if (SJBX.SelectedItem != null)
            {
                Area areaRow = (Area)SJBX.SelectedItem;
                DataTable table = SqlHelper.ExecuteDateTable("select * from areafull where AreaPid=@AreaPid", new SqlParameter("@AreaPid", areaRow.AreaId));
                XJBX.ItemsSource = GetAreas(table);
            }
            else
            {
                XJBX.ItemsSource = null;
            }
        }

        /// <summary>
        /// 数据转换对象
        /// </summary>
        /// <param name="table"></param>
        /// <returns></returns>
        private List<Area> GetAreas(DataTable table)
        {
            List<Area> lst = new List<Area>();
            foreach (DataRow item in table.Rows)
            {
                Area are = new Area();
                are.AreaId = Convert.ToInt32(item["Areaid"]);
                are.AreaName = item["AreaName"].ToString();
                are.AreaPid = Convert.ToInt32(item["AreaPid"]);
                lst.Add(are);
            }
            return lst;
        }