ASP.NET购物车

说明：该实例基于ASP.NET3.5使用Session实现购物车功能，数据库使用SqlServer2005。商品的分类以及产品的管理功能不在此实现。

         希望该实例能对对购物车功能实现不太清楚的开发人员起到抛砖引玉的功效:)。

         文中的产品图片来源于互联网。

1、惯例——预览功能

产品列表：当点击每个产品下的添加到购物车图片时，页面会转向到ShoppingCart.aspx同时传递一个当前产品的ID参数。

 

购物车：根据ID获取数据添加到DataTable，用Session存储，如果产品ID存在则不添加。

 

2、Products表设计

 

Product表模拟数据

 

3、数据访问类SqlHelper.cs

类图：

 

代码：

using System;

using  System.Data;
using  System.Data.SqlClient;

namespace  DAO
{
     public   class  SqlHelper
    {
         // 从Web.config中读取数据库连接字符春
         private  String ConnStr  =  System.Configuration.ConfigurationSettings.AppSettings[ " ConnString " ];

         private  SqlConnection conn  =   null ;

         ///   <summary>
         ///  将查询结果集填充到DataTable
         ///   </summary>
         ///   <param name="query"> 查询T-Sql </param>
         ///   <returns></returns>
         public  DataTable FillDataTable(String query)
        {
            DataTable dt  =   new  DataTable();
             using  (conn  =   new  SqlConnection(ConnStr))
            {
                SqlCommand cmd  =   new  SqlCommand();
                cmd.Connection  =  conn;
                cmd.CommandText  =  query;
                SqlDataAdapter ada  =   new  SqlDataAdapter();
                ada.SelectCommand  =  cmd;
                ada.Fill(dt);
            }
             return  dt;
        }

         ///   <summary>
         ///  将查询结果集填充到DataSet
         ///   </summary>
         ///   <param name="query"> 查询T-Sql,可以是多个Select语句 </param>
         ///   <returns></returns>
         public  DataSet FillDataSet(String query)
        {
            DataSet ds  =   new  DataSet();
             using  (conn  =   new  SqlConnection(ConnStr))
            {
                SqlCommand cmd  =   new  SqlCommand();
                cmd.Connection  =  conn;
                cmd.CommandText  =  query;
                SqlDataAdapter ada  =   new  SqlDataAdapter();
                ada.SelectCommand  =  cmd;
                ada.Fill(ds);
            }
             return  ds;
        }

         ///   <summary>
         ///  执行insert、update、delete、truncate语句
         ///   </summary>
         ///   <param name="commandText"> insert、update、delete、truncate语句 </param>
         public   void  ExecuteNonQuery(String commandText)
        {
             using  (conn  =   new  SqlConnection(ConnStr))
            {
                SqlTransaction tran  =  conn.BeginTransaction();
                 try
                {
                    SqlCommand cmd  =   new  SqlCommand();
                    cmd.Connection  =  conn;
                    cmd.Transaction  =  tran;
                    cmd.CommandText  =  commandText;
                    conn.Open();
                    cmd.ExecuteNonQuery();
                    tran.Commit();
                }
                 catch
                {
                    tran.Rollback();
                }
                 finally
                {
                    tran.Dispose();
                }
            }
        }

    }
}

4、产品列表功能实现ProductList.aspx

前台页面

DataList：显示产品列表

HyperLink：翻页

代码：

<% @ Page Language = " C# "  AutoEventWireup = " true "  CodeFile = " ProductList.aspx.cs "  Inherits = " ProductList "   %>

<! DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd" >
< html  xmlns ="http://www.w3.org/1999/xhtml" >
< head  runat ="server" >
     < title > 浏览产品列表 </ title >
     < link  href ="CSS/buy.css"  rel ="stylesheet"  type ="text/css"   />
</ head >
< body >
     < form  id ="form1"  runat ="server" >
     < div  id ="zone" >
         < div  align ="right"  class ="divBorder" >
             < a  href ="ShoppingCart.aspx" >
                 < img  src ="Images/cart.jpg"  alt ="我的购物车"  border ="0"  title ="查看购物车"   /></ a >
         </ div >
         < br  />
         < div >
             < asp:Button  ID ="btnRedirect"  runat ="server"  Text ="翻页很累，在火星可以显示所有产品"  
                onclick ="btnRedirect_Click"   />
         </ div >
         < br  />
         < div  align ="center"  class ="divBorder" >
             < asp:DataList  ID ="dlProducts"  runat ="server"  RepeatColumns ="3"  RepeatDirection ="Horizontal"
                OnItemDataBound ="dlProducts_ItemDataBound"  Width ="99%" >
                 < ItemTemplate >
                     < div >
                     < asp:Image  ID ="imgPic"  runat ="server"   />
                     </ div >
                     < div >
                     <% #  Eval ( " ProductName " )  %>
                     </ div >
                     < div >
                         < font  color ="gray" >< s > <% # Convert.ToInt32( Eval ( " MarketPrice " )).ToString( " c2 " )  %> </ s ></ font >
                         &nbsp;
                         < font  color ="red" > <% # Convert.ToInt32( Eval ( " BuyPrice " )).ToString( " c2 " ) %> </ font >
                     </ div >
                     < div >
                         < a  href ='ShoppingCart.aspx?ID=<%#  Eval("ID")% > &ProductNo = <% #  Eval ( " ProductNo " ) %> '> < img  src ="Images/addtocart.png"  alt ="添加到购物车"  border ="0"  title ="添加到购物车"   />   </ a >
                     </ div >
                 </ ItemTemplate >
             </ asp:DataList >
         </ div >
         < br  />
         < div  class ="divBorder" >
             < asp:Label  ID ="lblCurrentPage"  runat ="server" ></ asp:Label > /
             < asp:Label  ID ="lblPageCount"  runat ="server" ></ asp:Label > 页  &nbsp;
             < asp:HyperLink  ID ="lnkFirst"  runat ="server" > 首页 </ asp:HyperLink >
             &nbsp;
             < asp:HyperLink  ID ="lnkPrev"  runat ="server" > 上页 </ asp:HyperLink >
             &nbsp;
             < asp:HyperLink  ID ="lnkNext"  runat ="server" > 下页 </ asp:HyperLink >
             &nbsp;
             < asp:HyperLink  ID ="lnkLast"  runat ="server" > 末页 </ asp:HyperLink >
         </ div >
     </ div >
     </ form >
</ body >
</ html >

 用到的CSS代码：

body 
{
    font-size : 14px ;
    text-align : center ;
}
#zone
{
    margin : 0 auto ;
    width : 600px ;
}
.divBorder
{
    border-style : dashed ;
    border-width : thin ;
}
.tb
{
    width : 30px ;
}

PS：页面中关于价格的数字颜色和样式，请用CSS实现

后台代码：

using  System;
using  System.Web.UI.WebControls;
using  DAO;
using  System.Data;

public   partial   class  ProductList : System.Web.UI.Page
{
     protected   void  Page_Load( object  sender, EventArgs e)
    {
         if  ( ! IsPostBack)
        {
             this .BindList();
        }
    }

     private   void  BindList()
    {
        SqlHelper helper  =   new  SqlHelper();

        PagedDataSource pds  =   new  PagedDataSource();
        pds.DataSource  =  helper.FillDataTable( " Select * From Products Order By ID DESC " ).DefaultView;
        pds.AllowPaging  =   true ;
         if  (Request.QueryString[ " P " ]  !=   null )
        {
            pds.PageSize  =  ((DataView)pds.DataSource).Table.Rows.Count;
            btnRedirect.Text  =   " 浏览器发飙了，赶紧回地球吧 " ;
        }
         else
        {
            pds.PageSize  =   6 ;
            btnRedirect.Text  =   " 翻页很累，在火星可以显示所有产品 " ;
        }

         int  CurrentPage;
         if  (Request.QueryString[ " Page " ]  !=   null )
        {
            CurrentPage  =  Convert.ToInt32(Request.QueryString[ " Page " ]);
        }
         else
        {
            CurrentPage  =   1 ;
        }
        pds.CurrentPageIndex  =  CurrentPage  -   1 ;
        lblCurrentPage.Text  =  CurrentPage.ToString();
        lblPageCount.Text  =  pds.PageCount.ToString();
         if  ( ! pds.IsFirstPage)
        {
            lnkPrev.NavigateUrl  =  Request.CurrentExecutionFilePath  +   " ?Page= "   +  Convert.ToInt32(CurrentPage  -   1 );
            lnkFirst.NavigateUrl  =  Request.CurrentExecutionFilePath  +   " ?Page=1 " ;
        }
         if  ( ! pds.IsLastPage)
        {
            lnkNext.NavigateUrl  =  Request.CurrentExecutionFilePath  +   " ?Page= "   +  Convert.ToInt32(CurrentPage  +   1 );
                lnkLast.NavigateUrl  =  Request.CurrentExecutionFilePath  +   " ?Page= "   +  pds.PageCount;
        }

        dlProducts.DataSource  =  pds;
        dlProducts.DataBind();
    }
     protected   void  dlProducts_ItemDataBound( object  sender, DataListItemEventArgs e)
    {
         if  (e.Item.ItemType  ==  ListItemType.Item  ||  e.Item.ItemType  ==  ListItemType.AlternatingItem)
        {
            DataRowView drv  =  (DataRowView)e.Item.DataItem;

            ((Image)e.Item.FindControl( " imgPic " )).ImageUrl  =   " ~/Images/Products/ "   +  drv[ " PicturePath " ].ToString();
        }
    }
     protected   void  btnRedirect_Click( object  sender, EventArgs e)
    {
         if  (btnRedirect.Text  ==   " 翻页很累，在火星可以显示所有产品 " )
        {
            Response.Redirect( " ProductList.aspx?P=1 " );
        }
         else
        {
            Response.Redirect( " ProductList.aspx " );
        }
    }
}

 5、购物车功能实现ShoppingCart.aspx

前台页面：

 

<% @ Page Language = " C# "  AutoEventWireup = " true "  CodeFile = " ShoppingCart.aspx.cs "  Inherits = " ShoppingCart "   %>

<! DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd" >
< html  xmlns ="http://www.w3.org/1999/xhtml" >
< head  runat ="server" >
     < title > 我的购物车 </ title >
     < link  href ="CSS/buy.css"  rel ="stylesheet"  type ="text/css"   />

     < script  type ="text/javascript" >
         // 点击+号图，数量+1
         function  Plus(obj) {
            obj.value  =  parseInt(obj.value)  +   1 ;
        }
         // 数量-1
         function  Reduce(obj) {
             if  (obj.value  >   1 ) {
                obj.value  =  obj.value  -   1 ;
            }
        }
         // 替换txtAmount文本框非整数的输入
         // 数据整个不合法时置1
         function  CheckValue(obj) {
             var  v  =  obj.value.replace( / [^\d] / g,  '' );
             if  (v  ==   ''   ||  v  ==   ' NaN ' ) {
                obj.value  =   " 1 " ;
            }
             else  {
                obj.value  =  v;
            }
        }
     </ script >

</ head >
< body >
     < form  id ="form1"  runat ="server" >
     < div  id ="zone" >
         < div  align ="left"  class ="divBorder" >
             < img  src ="Images/back.jpg"  onclick ="javascript:location.href='ProductList.aspx';"
                style ="cursor: hand"  alt ="返回产品列表"  border ="0"  title ="返回产品列表"   />
             < img  src ="Images/cart_001.gif"  alt ="我的购物车"   />
         </ div >
         < br  />
         < div  class ="divBorder" >
             < asp:GridView  ID ="gvCart"  runat ="server"  DataKeyNames ="ID"  AutoGenerateColumns ="False"
                ShowFooter ="True"  Width ="98%"  OnRowDataBound ="gvCart_RowDataBound"  OnRowDeleting ="gvCart_RowDeleting" >
                 < Columns >
                     < asp:BoundField  DataField ="ProductNo"  HeaderText ="产品编号" >
                         < ItemStyle  Width ="80px"   />
                     </ asp:BoundField >
                     < asp:BoundField  DataField ="ProductName"  HeaderText ="产品名称"   />
                     < asp:TemplateField  HeaderText ="产品单价" >
                         < ItemStyle  Width ="80px"   />
                         < ItemTemplate >
                             <% # Convert.ToInt32( Eval ( " BuyPrice " )).ToString( " c2 " )  %>
                         </ ItemTemplate >
                     </ asp:TemplateField >
                     < asp:TemplateField  HeaderText ="数量" >
                         < ItemStyle  Width ="80px"   />
                         < ItemTemplate >
                             < img  src ="Images/bag_close.gif"  id ="imgReduce"  runat ="server"   />
                             < asp:TextBox  ID ="txtAmount"  Width ="20px"  Height ="16px"  runat ="server"  Text ='<%#  Eval("Amount") % > '
                                onkeyup="CheckValue(this)"> </ asp:TextBox >
                             < img  src ="Images/bag_open.gif"  id ="imgPlus"  runat ="server"   />
                         </ ItemTemplate >
                     </ asp:TemplateField >
                     < asp:CommandField  HeaderText ="删除"  DeleteText ="删除"  ShowDeleteButton ="true" >
                         < ItemStyle  Width ="30px"   />
                     </ asp:CommandField >
                 </ Columns >
                 < EmptyDataTemplate >
                    您的购物车中没有任何商品。
                 </ EmptyDataTemplate >
                 < AlternatingRowStyle  BackColor ="WhiteSmoke"   />
             </ asp:GridView >
         </ div >
         < br  />
         < div >
             < a  href ="ProductList.aspx" >
                 < img  src ="Images/go_on.gif"  border ="0"   /></ a > &nbsp; < asp:ImageButton  ID ="imgbtnTotal"
                    runat ="server"  ImageUrl ="~/Images/updatecart.gif"  OnClick ="imgbtnTotal_Click"   />
             &nbsp; < img  src ="Images/pay.gif"   />
         </ div >
     </ div >
     </ form >
</ body >
</ html >

后台代码：

using  System;
using  System.Collections.Generic;
using  System.Linq;
using  System.Web;
using  System.Web.UI;
using  System.Web.UI.WebControls;
using  System.Web.UI.HtmlControls;
using  System.Data;
using  DAO;
using  System.Drawing;

public   partial   class  ShoppingCart : System.Web.UI.Page
{
     // 整型变量，用于存储总金额
     private  Int32 Total  =   0 ;
     protected   void  Page_Load( object  sender, EventArgs e)
    {
         if  ( ! IsPostBack)
        {
            BindCartList();
        }
    }

     private   void  BindCartList()
    {
        DataTable dt  =   new  DataTable();

         // 如果Session变量存在，则直接获取
         if  (Session[ " Cart " ]  !=   null )
        {
            dt  =  (DataTable)Session[ " Cart " ];
        }
         else // 如果Session变量不存在，创建存储数据的表结构
        {
            dt.Columns.Add( new  DataColumn( " ID " ,  typeof (Int32)));
            dt.Columns.Add( new  DataColumn( " ProductNo " ,  typeof (String)));
            dt.Columns.Add( new  DataColumn( " ProductName " ,  typeof (String)));
            dt.Columns.Add( new  DataColumn( " BuyPrice " ,  typeof (String)));
            dt.Columns.Add( new  DataColumn( " Amount " ,  typeof (Int32)));
        }
         // ID或ProductNo不为null
         // 则表示选中一件商品添加到购物车
         if  (ID  !=   null )
        {
             // 先判断购物车中是否已经存在该商品
            Boolean IsExist  =   false ;
             foreach  (DataRow dr  in  dt.Rows)
            {
                 if  (dr[ " ProductNo " ].ToString()  ==  ProductNo)
                {
                    IsExist  =   true ;
                     break ;
                }
            }
             // 如果购物车中存在该商品，则提示客户
             // 该商品不会被重复添加到购物车
             if  (IsExist)
            {
                ScriptManager.RegisterStartupScript(
                     this ,  typeof (Page),  " alertExist " ,  " alert('您选择的商品（编号： "   +  ProductNo  +   " ）已在购物车存在！') " ,  true );
            }
             else // 如果购物车中不存在该商品，则添加到购物车
            {
                SqlHelper helper  =   new  SqlHelper();
                DataTable dtRow  =  helper.FillDataTable(
                    String.Format( " Select * From Products Where ID={0} " , ID.ToString()));
                dt.Rows.Add( new   object []{
                    Convert.ToInt32(ID.ToString()),
                    dtRow.Rows[ 0 ][ " ProductNo " ].ToString(),
                    dtRow.Rows[ 0 ][ " ProductName " ].ToString(),
                    Convert.ToInt32(dtRow.Rows[ 0 ][ " BuyPrice " ].ToString()),
                     1 });
            }
        }

        gvCart.DataSource  =  dt;
        gvCart.DataBind();

        Session[ " Cart " ]  =  dt;
    }

     protected   void  gvCart_RowDataBound( object  sender, GridViewRowEventArgs e)
    {
         if  (e.Row.RowType  ==  DataControlRowType.DataRow)
        {
             // GridView行的加亮显示功能
            e.Row.Attributes.Add( " onmouseover " ,  " b=this.style.backgroundColor;this.style.backgroundColor='#E1ECEE' " );
            e.Row.Attributes.Add( " onmouseout " ,  " this.style.backgroundColor=b " );

             // 给+号图片和-号图片添加客户端click事件
             // 用JavaScript实现数量的+1和-1
            TextBox tb  =  (TextBox)e.Row.FindControl( " txtAmount " );
            ((HtmlImage)e.Row.FindControl( " imgReduce " )).Attributes.Add( " onclick " ,  " Reduce( "   +  tb.ClientID  +   " ) " );
            ((HtmlImage)e.Row.FindControl( " imgPlus " )).Attributes.Add( " onclick " ,  " Plus( "   +  tb.ClientID  +   " ) " );
            
             // 根据商品单价和数量计算购物车中商品的总金额
            DataRowView drv  =  (DataRowView)e.Row.DataItem;
            Total  +=  Int32.Parse(drv[ " BuyPrice " ].ToString()) * Int32.Parse(tb.Text);
        }
         if  (e.Row.RowType  ==  DataControlRowType.Footer)
        {
             // 将总金额显示在金额一列对应的Footer单元格
            e.Row.Cells[ 1 ].Text  =   " 金额总计： " ;
            e.Row.Cells[ 1 ].HorizontalAlign  =  HorizontalAlign.Right;
            e.Row.Cells[ 2 ].Text  =  Total.ToString( " c2 " );
            e.Row.Cells[ 2 ].ForeColor  =  Color.Red;
        }
    }
     protected   void  gvCart_RowDeleting( object  sender, GridViewDeleteEventArgs e)
    {
         // 点击删除时从DataTable中删除对应的数据行
         if  (Session[ " Cart " ]  !=   null )
        {
            DataTable dt  =  (DataTable)Session[ " Cart " ];
            dt.Rows.RemoveAt(e.RowIndex);
            dt.AcceptChanges();
            Session[ " Cart " ]  =  dt;
            Response.Redirect( " ShoppingCart.aspx " );
        }
    }
     protected   void  imgbtnTotal_Click( object  sender, ImageClickEventArgs e)
    {
         // 遍历GridView，根据每行的文本框中的值
         // 修改DataTable中对应行中数量一列的值
         if  (Session[ " Cart " ]  !=   null )
        {
            DataTable dt  =  (DataTable)Session[ " Cart " ];
             for  ( int  i  =   0 ; i  <  gvCart.Rows.Count; i ++ )
            {
                dt.Rows[i][ " Amount " ]  =  ((TextBox)gvCart.Rows[i].FindControl( " txtAmount " )).Text;
            }
            dt.AcceptChanges();
            Session[ " Cart " ]  =  dt;
            Response.Redirect( " ShoppingCart.aspx " );
        }
    }

     #region  属性
     ///   <summary>
     ///  get URL参数ID的值，定义为Nullable <Int32> 类型
     ///   </summary>
     private  Int32 ?  ID
    {
         get
        {
             try
            {
                 return  Int32.Parse(Request.QueryString[ " ID " ]);
            }
             catch
            {
                 return   null ;
            }
        }
    }
     ///   <summary>
     ///  get URL参数ProductNo的值
     ///   </summary>
     private  String ProductNo
    {
         get
        {
            return  Request.QueryString[ " ProductNo " ];
        }
    }
     #endregion
}