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？

image_thumb[1]

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

image_thumb[2]

image_thumb[3]

image_thumb[4]

image_thumb[5]

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:  }
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原文地址：https://www.cnblogs.com/iceicebaby/p/2446064.html