用简单的修改数据理解三层概念

项目文件列表：

文件中值得注意的代码：

DataManager.cs：

        public List<TableModel> GetDataList()
        {
            List<TableModel> models;
            SqlHelper sqlhelper = new SqlHelper();
            string sql = "select * from MyOrders";
            using (SqlDataReader reader = sqlhelper.ExecuteReader(sql, null))
            {
                if (reader.HasRows)
                {
                    models = new List<TableModel>();
                    while (reader.Read())
                    {
                        TableModel model = new TableModel();
                        model.ID = int.Parse(reader[0].ToString());
                        model.Name = reader[1].ToString();
                        model.Number = reader[2].ToString();
                        model.Count = reader.IsDBNull(3) ? null : (int?)reader.GetInt32(3);
                        model.Price = reader.GetInt32(4);
                        model.Purchaser = reader.IsDBNull(5) ? string.Empty : reader.GetString(5);
                        model.DateTime = reader.IsDBNull(6) ? null : (DateTime?)reader.GetDateTime(6);
                        model.Salesman = reader.IsDBNull(7) ? string.Empty : reader[7].ToString();
                        models.Add(model);
                    }
                    return models;
                }
            }
            return null;
        }

TableModel.cs

    public class TableModel
    {
        /// <summary>
        /// 数据模型:
        ///     像DataGridView一样的数据绑定控件,只认识属性(Model中的属性名称),
        /// 不识别(认)字段。与表中的列的名称不是一回事.但是可以获得表中的列名，
        /// 并设置在DataGridView中的列名上。
        /// </summary>
        public TableModel()
        {

        }
        /// <summary>
        /// id
        /// </summary>
        public int ID { get; set; }
        /// <summary>
        /// 商品名称
        /// </summary>
        public string Name { get; set; }
        /// <summary>
        /// 商品编号
        /// </summary>
        public string Number { get; set; }
        /// <summary>
        /// 销售数量
        /// </summary>
        public int? Count { get; set; }
        /// <summary>
        /// 销售价格
        /// </summary>
        public int Price { get; set; }
        /// <summary>
        /// 购买人
        /// </summary>
        public string Purchaser { get; set; }
        /// <summary>
        /// 销售日期
        /// </summary>
        public DateTime? DateTime { get; set; }
        /// <summary>
        /// 销售员
        /// </summary>
        public string Salesman { get; set; }
    }

全部项目文件：http://pan.baidu.com/s/1o6rwEFo