牛腩购物网25：购物车的实现

第二部分：购物车的实现

我们用session来保存购物车，用一个哈希表来保存商品

购物车

商品1：单价，数量

商品2：单价，数量

商品3：单价，数量

购物车中的每一个商品，都是一个对象，这个对象，有单价，和数量这2个属性，购物车是很多对象的集合。

我们在model层中，增加一个 ShopItem 类， 这个就是表示 购物车 商品类

还增加一个 ShopCart 类，这个就是购物车类，里面有很多对 购物车商品的方法

ShopItem.cs

 1:  using System;

 2:  using System.Collections.Generic;

 3:  using System.Linq;

 4:  using System.Text;

 5:  

 6:  namespace Niunan.Shop.Model

 7:  {

 8:     public class ShopItem

 9:      {

10:         //这里用到 asp.net 3.5的 自动属性

11:  

12:         public int proid { get; set; }       //商品ID

13:         public decimal price { get; set; }   //商品的价格

14:         public int quantity { set; get; }    //商品的数量

15:  

16:  

17:      }

18:  }

19:  

ShopCart.cs

  1:  using System;

  2:  using System.Collections.Generic;

  3:  using System.Linq;

  4:  using System.Text;

  5:  using System.Collections;// 如果我们要使用  哈希表 ，就需要引用这个集合

  6:  

  7:  namespace Niunan.Shop.Model

  8:  {

  9:      /// <summary>购物车类

 10:      /// 

 11:      /// </summary>

 12:      public class ShopCart

 13:      {

 14:          private Hashtable _sc = new Hashtable();

 15:  

 16:          /// <summary>向购物车中，添加商品

 17:          /// 

 18:          /// </summary>

 19:          /// <param name="proid">商品的ID</param>

 20:          /// <param name="item">商品</param>

 21:          public void Add(int proid, ShopItem item)

 22:          {

 23:              //先判断这个商品是否存在

 24:              if (_sc[proid] == null)

 25:              {

 26:                  //不存在

 27:                  _sc.Add(proid, item);

 28:              }

 29:              else

 30:              {

 31:                  //如果存在，我们先把商品取出来，然后给商品的数量+1

 32:  

 33:                  ShopItem si = _sc[proid] as ShopItem;   //这里的 _sc[proid]  是指根据商品ID，获取对应的值,

 34:  这个值是个object 我们需要转换为 shopitem

 35:                  si.quantity += 1;

 36:                  _sc[proid] = si;

 37:              }

 38:          }

 39:  

 40:          /// <summary>删除购物车中的商品

 41:          /// 

 42:          /// </summary>

 43:          /// <param name="proid">商品的ID</param>

 44:          public void Delete(int proid)

 45:          {

 46:              if (_sc[proid] != null)

 47:              {

 48:                  _sc.Remove(proid);

 49:              }

 50:  

 51:          }

 52:  

 53:          /// <summary>修改购物车中商品的数量

 54:          /// 

 55:          /// </summary>

 56:          /// <param name="proid">商品id</param>

 57:          /// <param name="quantity">数量</param>

 58:          public void Update(int proid, int quantity)

 59:          {

 60:              //先判断有无商品

 61:              if (_sc[proid] != null)

 62:              {

 63:                  ShopItem si = _sc[proid] as ShopItem;

 64:                  //如果数量>0 那么就直接修改数量，否则数量为0的话，就删除掉这个商品

 65:                  if (quantity > 0)

 66:                  {

 67:                      si.quantity = quantity;

 68:                  }

 69:                  else

 70:                  {

 71:                      _sc.Remove(proid);

 72:                  }

 73:  

 74:              }

 75:          }

 76:          /// <summary>获取购物车中商品的种类的数量，例如是有多少种商品

 77:          /// 

 78:          /// </summary>

 79:          /// <returns></returns>

 80:          public int GetItemCount()

 81:          {

 82:              return _sc.Count;  //返回的是  哈希table 键/值 对的数量

 83:          }

 84:  

 85:          /// <summary>返回购物车中商品的总价

 86:          /// 

 87:          /// </summary>

 88:          /// <returns></returns>

 89:          public decimal GetTotalPrice()

 90:          {

 91:              decimal total = 0;

 92:              //这里的 _sc.Value 是一个 iCollection， i 表示 Interface, 也就是表示是一个集合的接口

 93:              //如果是要绑定 gridview 或者是 repeater 等数据控件  ，必须要实现 icollection接口

 94:              foreach (ShopItem item in _sc.Values)

 95:              {

 96:                  total += item.price * item.quantity;

 97:              }

 98:              return total;

 99:          }

100:  

101:          /// <summary>获取购物车中商品的集合，用于绑定数据控件

102:          /// 

103:          /// </summary>

104:          /// <returns></returns>

105:          public ICollection GetItemList()

106:          {

107:              //这里的 _sc.Value 是一个 iCollection， i 表示 Interface, 也就是表示是一个集合的接口

108:              //如果是要绑定 gridview 或者是 repeater 等数据控件  ，必须要实现 icollection接口

109:              return _sc.Values;

110:          }

111:  

112:      }

113:  }

114:  

我们来建立一个测试页面，来测试购物车。

前台test.aspx 代码

 1:  <%@ Page Language="C#" AutoEventWireup="true" CodeBehind="test.aspx.cs" Inherits="Niunan.Shop.Web.test" %>

 2:  

 3:  <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

 4:  

 5:  <html xmlns="http://www.w3.org/1999/xhtml">

 6:  <head runat="server">

 7:      <title></title>

 8:  </head>

 9:  <body>

10:      <form id="form1" runat="server">

11:      <div>

12:      

13:          <asp:Button ID="Button1" runat="server" Text="添加商品1" CommandArgument="1"  OnClick="buy"/>

14:          <asp:Button ID="Button2" runat="server" Text="添加商品2" CommandArgument="2"  OnClick="buy"/>

15:          <asp:Button ID="Button3" runat="server" Text="添加商品3" CommandArgument="3"  OnClick="buy"/>

16:          <asp:Button ID="Button4" runat="server" Text="添加商品4" CommandArgument="4"  OnClick="buy"/>

17:          <asp:Button ID="Button5" runat="server" Text="添加商品5" CommandArgument="5"  OnClick="buy"/>

18:      

19:      </div>

20:          <div>

21:              购物车中商品的种类：

22:              <asp:Literal ID="litCount" runat="server"></asp:Literal><br />

23:  

24:              购物车中商品的总价

25:              <asp:Literal ID="litTotalPrice" runat="server"></asp:Literal>

26:  

27:              <br />

28:              <br />

29:              <asp:GridView ID="gdCart" runat="server">

30:              </asp:GridView>

31:  

32:          </div>

33:      </form>

34:  </body>

35:  </html>

36:  

后台代码：

 1:  using System;

 2:  using System.Collections.Generic;

 3:  using System.Linq;

 4:  using System.Web;

 5:  using System.Web.UI;

 6:  using System.Web.UI.WebControls;

 7:  

 8:  namespace Niunan.Shop.Web

 9:  {

10:      public partial class test : System.Web.UI.Page

11:      {

12:          protected void Page_Load(object sender, EventArgs e)

13:          {

14:              if (Session["cart"]!=null)

15:              {

16:                  Niunan.Shop.Model.ShopCart sc = Session["cart"] as Niunan.Shop.Model.ShopCart;

17:                  litCount.Text = sc.GetItemCount().ToString();

18:                  litTotalPrice.Text = sc.GetTotalPrice().ToString("c2");

19:                  gdCart.DataSource = sc.GetItemList();

20:                  gdCart.DataBind();

21:              }

22:          }

23:  

24:          protected void buy(object sender, EventArgs e)

25:          {

26:              string proid = (sender as  Button).CommandArgument;

27:  

28:              decimal price = int.Parse(proid) * 10;

29:  

30:              if (Session["cart"] != null)

31:              {

32:                  //如果不等于空的话，我们就先取出来，然后再加进去

33:                  Niunan.Shop.Model.ShopCart sc = Session["cart"] as Niunan.Shop.Model.ShopCart;

34:                  sc.Add(int.Parse(proid),new Model.ShopItem{

35:                  proid=int.Parse(proid),price=price,quantity=1

36:                  });

37:                  Session["cart"] = sc;

38:  

39:              }

40:              else

41:              {

42:                  Niunan.Shop.Model.ShopCart sc = new Model.ShopCart();

43:                  sc.Add(int.Parse(proid), new Model.ShopItem {

44:                      proid = int.Parse(proid),

45:                      price = price,

46:                      quantity = 1

47:                  });

48:  

49:                  //然后把购物车，放到session里面

50:                  Session["cart"] = sc;

51:              }

52:  

53:              Response.Redirect(Request.Url.ToString());

54:              

55:  

56:          }

57:      }

58:  }

前台的样式如下，但是，这里的girdview是我们自带的，如果我们想要修改，怎么弄呢？

我们先禁用girdview的 自动显示字段， AutoGenerateColumns="false" 然后我们开始编辑列

最后，前台代码如下：

 1:  <%@ Page Language="C#" AutoEventWireup="true" CodeBehind="test.aspx.cs" Inherits="Niunan.Shop.Web.test" %>

 2:  

 3:  <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

 4:  <html xmlns="http://www.w3.org/1999/xhtml">

 5:  <head runat="server">

 6:      <title></title>

 7:  </head>

 8:  <body>

 9:      <form id="form1" runat="server">

10:      <div>

11:          <asp:Button ID="Button1" runat="server" Text="添加商品1" CommandArgument="1" OnClick="buy" />

12:          <asp:Button ID="Button2" runat="server" Text="添加商品2" CommandArgument="2" OnClick="buy" />

13:          <asp:Button ID="Button3" runat="server" Text="添加商品3" CommandArgument="3" OnClick="buy" />

14:          <asp:Button ID="Button4" runat="server" Text="添加商品4" CommandArgument="4" OnClick="buy" />

15:          <asp:Button ID="Button5" runat="server" Text="添加商品5" CommandArgument="5" OnClick="buy" />

16:      </div>

17:      <div>

18:          购物车中商品的种类：

19:          <asp:Literal ID="litCount" runat="server"></asp:Literal><br />

20:          购物车中商品的总价

21:          <asp:Literal ID="litTotalPrice" runat="server"></asp:Literal>

22:          <br />

23:          <br />

24:          <asp:GridView ID="gdCart" runat="server" EnableModelValidation="True" AutoGenerateColumns="False">

25:              <Columns>

26:                  <asp:BoundField DataField="proid" HeaderText="商品ID" />

27:                  <asp:BoundField DataField="price" HeaderText="价格" />

28:                  <asp:TemplateField HeaderText="数量">

29:                      <ItemTemplate>

30:                          <asp:TextBox ID="TextBox1" runat="server" Text='<%#Eval("quantity") %>' ToolTip='<%#Eval("proid") %>' AutoPostBack="true" OnTextChanged="Mod"></asp:TextBox>

31:                      </ItemTemplate>

32:                  </asp:TemplateField>

33:                  <asp:TemplateField HeaderText="小计">

34:                      <ItemTemplate>

35:                          <%# decimal.Parse(Eval("price").ToString()) * int.Parse(Eval("quantity").ToString()) %>￥

36:                      </ItemTemplate>

37:                  </asp:TemplateField>

38:                  <asp:TemplateField HeaderText="操作">

39:                      <ItemTemplate>

40:                          <asp:LinkButton ID="LinkButton1" runat="server" OnClick="delete" CommandArgument='<%#Eval("proid") %>'>删除</asp:LinkButton>

41:                      </ItemTemplate>

42:                  </asp:TemplateField>

43:              </Columns>

44:          </asp:GridView>

45:          <br />

46:          <br />

47:      </div>

48:      </form>

49:  </body>

50:  </html>

51:  

后台代码：

  1:  using System;

  2:  using System.Collections.Generic;

  3:  using System.Linq;

  4:  using System.Web;

  5:  using System.Web.UI;

  6:  using System.Web.UI.WebControls;

  7:  

  8:  

  9:  namespace Niunan.Shop.Web

 10:  {

 11:      public partial class test : System.Web.UI.Page

 12:      {

 13:          protected void Page_Load(object sender, EventArgs e)

 14:          {

 15:              if (!Page.IsPostBack)   //回发的时候，我们会在page_load  看到页面上所有的控件的值，在回发的时候都被保存了下来，并且可以访问

 16:              {

 17:                  if (Session["cart"] != null)

 18:                  {

 19:                      Niunan.Shop.Model.ShopCart sc = Session["cart"] as Niunan.Shop.Model.ShopCart;

 20:                      litCount.Text = sc.GetItemCount().ToString();

 21:                      litTotalPrice.Text = sc.GetTotalPrice().ToString("c2");

 22:                      gdCart.DataSource = sc.GetItemList();

 23:                      gdCart.DataBind();

 24:                  }

 25:              }

 26:          }

 27:  

 28:          //购买

 29:          protected void buy(object sender, EventArgs e)

 30:          {

 31:              string proid = (sender as Button).CommandArgument;

 32:  

 33:              decimal price = int.Parse(proid) * 10;

 34:  

 35:              if (Session["cart"] != null)

 36:              {

 37:                  //如果不等于空的话，我们就先取出来，然后再加进去

 38:                  Niunan.Shop.Model.ShopCart sc = Session["cart"] as Niunan.Shop.Model.ShopCart;

 39:                  sc.Add(int.Parse(proid), new Model.ShopItem

 40:                  {

 41:                      proid = int.Parse(proid),

 42:                      price = price,

 43:                      quantity = 1

 44:                  });

 45:                  Session["cart"] = sc;

 46:  

 47:              }

 48:              else

 49:              {

 50:                  Niunan.Shop.Model.ShopCart sc = new Model.ShopCart();

 51:                  sc.Add(int.Parse(proid), new Model.ShopItem

 52:                  {

 53:                      proid = int.Parse(proid),

 54:                      price = price,

 55:                      quantity = 1

 56:                  });

 57:  

 58:                  //然后把购物车，放到session里面

 59:                  Session["cart"] = sc;

 60:              }

 61:  

 62:              Response.Redirect(Request.Url.ToString());

 63:  

 64:  

 65:          }

 66:  

 67:          //修改购物车中商品的数量

 68:          protected void Mod(object sender, EventArgs e)

 69:          {

 70:              TextBox txt = (sender as TextBox);  //这里是 TextBox 获取的方法  ,先转换为一个 TextBox 对象

 71:              string proid = txt.ToolTip;

 72:              string quantity = txt.Text;

 73:              int x;

 74:              //如果数量不能转换，我们就强制数量为1

 75:              if (!int.TryParse(quantity, out x))

 76:              {

 77:                  x = 1;

 78:              }

 79:              if (Session["cart"] != null)

 80:              {

 81:                  //如果不等于空的话，我们就先取出来，然后再加进去

 82:                  Niunan.Shop.Model.ShopCart sc = Session["cart"] as Niunan.Shop.Model.ShopCart;

 83:                  sc.Update(int.Parse(proid), x);

 84:                  Session["cart"] = sc;

 85:  

 86:              }

 87:              Response.Redirect(Request.Url.ToString());

 88:  

 89:          }

 90:  

 91:          //删除购物车中的商品

 92:          protected void delete(object sender, EventArgs e)

 93:          {

 94:              string proid = (sender as LinkButton).CommandArgument;

 95:              if (Session["cart"] != null)

 96:              {

 97:                  Niunan.Shop.Model.ShopCart sc = Session["cart"] as Niunan.Shop.Model.ShopCart;

 98:                  sc.Delete(int.Parse(proid));

 99:                  Session["cart"] = sc;

100:                  Response.Redirect(Request.Url.ToString());

101:              }

102:  

103:          }

104:  

105:  

106:  

107:  

108:      }

109:  }