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petshop4充分体现了面向接口编程的思想，就是给你一个接口你别管我是怎么实现的，你只管用别说其他的。
namespace PetShop.BLL {
/// <summary>
/// A business component to manage products
/// </summary>
public class Product {
// Get an instance of the Product DAL using the DALFactory
// Making this static will cache the DAL instance after the initial load private static readonly IProduct dal = PetShop.DALFactory.DataAccess.CreateProduct(); |
在bll层，这里使用创建Produce的接口，你只管调用他的方法。
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namespace PetShop.IDAL
{
/// <summary>
/// Interface for the Product DAL
/// </summary>
public interface IProduct
{
/// <summary>
/// Method to search products by category name
/// </summary>
/// <param name="category">Name of the category to search by</param>
/// <returns>Interface to Model Collection Generic of search results</returns> IList<ProductInfo> GetProductsByCategory(string category);
/// <summary>
/// Method to search products by a set of keyword
/// </summary>
/// <param name="keywords">An array of keywords to search by</param>
/// <returns>Interface to Model Collection Generic of search results</returns> IList<ProductInfo> GetProductsBySearch(string[] keywords);
/// <summary>
/// Query for a product
/// </summary>
/// <param name="productId">Product Id</param>
/// <returns>Interface to Model ProductInfo for requested product</returns> ProductInfo GetProduct(string productId); } |
这里是定义了Product接口和他的虚方法。
namespace PetShop.SQLServerDAL {
public class Product : IProduct {
//Static constants private const string SQL_SELECT_PRODUCTS_BY_CATEGORY = "SELECT Product.ProductId, Product.Name, Product.Descn, Product.Image, Product.CategoryId FROM Product WHERE Product.CategoryId = @Category"; private const string SQL_SELECT_PRODUCTS_BY_SEARCH1 = "SELECT ProductId, Name, Descn, Product.Image, Product.CategoryId FROM Product WHERE (("; private const string SQL_SELECT_PRODUCTS_BY_SEARCH2 = "LOWER(Name) LIKE '%' + {0} + '%' OR LOWER(CategoryId) LIKE '%' + {0} + '%'"; private const string SQL_SELECT_PRODUCTS_BY_SEARCH3 = ") OR ("; private const string SQL_SELECT_PRODUCTS_BY_SEARCH4 = "))"; private const string SQL_SELECT_PRODUCT = "SELECT Product.ProductId, Product.Name, Product.Descn, Product.Image, Product.CategoryId FROM Product WHERE Product.ProductId = @ProductId"; private const string PARM_CATEGORY = "@Category"; private const string PARM_KEYWORD = "@Keyword"; private const string PARM_PRODUCTID = "@ProductId";
/// <summary>
/// Query for products by category
/// </summary>
/// <param name="category">category name</param>
/// <returns>A Generic List of ProductInfo</returns> public IList<ProductInfo> GetProductsByCategory(string category) {
IList<ProductInfo> productsByCategory = new List<ProductInfo>(); |
这里是实现Product接口的类，
namespace PetShop.DALFactory {
/// <summary>
/// This class is implemented following the Abstract Factory pattern to create the DAL implementation
/// specified from the configuration file
/// </summary> public sealed class DataAccess {
// Look up the DAL implementation we should be using private static readonly string path = ConfigurationManager.AppSettings["WebDAL"]; private static readonly string orderPath = ConfigurationManager.AppSettings["OrdersDAL"]; private DataAccess() { }
public static PetShop.IDAL.ICategory CreateCategory() { string className = path + ".Category"; return (PetShop.IDAL.ICategory)Assembly.Load(path).CreateInstance(className); } |
这里是利用工厂模式来映射你需要你想创建哪一个。
后面还有一些消息队列MSMQMessage利用cache缓存以后达到异步处理购物车里订单的功能！
刚开始看应先从先从Product入口，关于Product的一些操作串联起来看一遍！
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