商城中，购物车的实现(DataTable和Session)

最近在做一个商城购物的一部分，用到了购物车，因为是刚参加工作，对购物这方面，不太了解，所以用自己的方法作了一个购物车，在网上查了查资料，有的用数据库纪录购物车信息的，有的用Session纪录的，由于时间的原因，我用的是Session,如果各位有更好的建议或意见，不妨在此讨论一下，共同进步，共同学习！
    一下是源代码，我在里面用的都是图片，可能用的时候图片显示不出来，在一个我用的是三层架构的，所以在用的时候把它改成您们所用的就行了
//------------------------------------------------------------------------------------------Html------------------------------------------------------------------------


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

<!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>无标题页</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
        <table>
            <tr>
                <td colspan="4">
                    <asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False" ShowFooter="True" OnRowDataBound="GridView1_RowDataBound">
                        <Columns>
                            <asp:BoundField DataField="Pro_Id" Visible="False" />
                            <asp:TemplateField HeaderText="产品名称">
                            <ItemTemplate>
                            <%#Eval("Pro_Name") %>
                            </ItemTemplate>
                            </asp:TemplateField>
                            <asp:TemplateField HeaderText="数量">
                            <ItemTemplate>
                                <asp:TextBox ID="txtproquantity" runat="server" Width="51px" Text='<%#Eval("Pro_Quantity") %>'></asp:TextBox>
                            </ItemTemplate>
                                <ItemStyle HorizontalAlign="Center" />
                            </asp:TemplateField>
                            <asp:TemplateField HeaderText="单价">
                            <ItemTemplate>
                            <%#Eval("Pro_Price") %>
                            </ItemTemplate>

                                <ItemStyle HorizontalAlign="Center" />
                            </asp:TemplateField>
                            <asp:TemplateField HeaderText="价格">
                            <ItemTemplate>
                            <%#Eval("Pro_SubTotal") %>
                            </ItemTemplate>
                            <FooterTemplate>
                                    总共：<%=dTotal %>元
                                </FooterTemplate>
                            </asp:TemplateField>
                        </Columns>
                    </asp:GridView>
                </td>
            </tr>
            <tr>
                <td style=" 100px">
                    <asp:ImageButton ID="ImageButton1" runat="server" ImageUrl="~/Images/cart_clear_zh.gif"
                        OnClick="ImageButton1_Click" /></td>
                <td style=" 100px">
                    <asp:ImageButton ID="ImageButton2" runat="server" ImageUrl="~/Images/cart_change_zh.gif" OnClick="ImageButton2_Click" /></td>
                <td style=" 100px">
                    <asp:ImageButton ID="ImageButton3" runat="server" ImageUrl="~/Images/cart_continue_zh.gif"
                        OnClick="ImageButton3_Click" /></td>
                <td style=" 100px">
                    <asp:ImageButton ID="ImageButton4" runat="server" ImageUrl="~/Images/cart_next_zh.gif" OnClick="ImageButton4_Click" /></td>
            </tr>
        </table>

    </div>
    </form>
</body>
</html>
//-----------------------------------------------------------------------------------------。Cs------------------------------------------------------------------------
/**************************************************************
*
* Copyright (C)1995-2006 .
*
* Author      : 兴百放
* Create Date : 2007-3-28
* Summary     : 购物车管理
*
*
* Modified By :
* Date        :
* Mail        : xbf321@163.com Or xbf321@tom.com
* Blog        : blog.csdn.net/xbf321
**************************************************************/
using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Collections.Generic;

public partial class Cart : System.Web.UI.Page
{
    private string _Pro_Id;
    DataTable CartTable = new DataTable();  //声明一个DataTable对象
    DataRow dr;
    public Double dTotal = 0.00;            //总计款额
    protected void Page_Load(object sender, EventArgs e)
    {

        if(!Page.IsPostBack)
        {
            if (Session["CartShop"] == null)                                       //判断是否为第一次添加购物车否则创建DataTable
            {
                CartTable.Columns.Add(new DataColumn("Pro_Id", typeof(string)));
                CartTable.Columns.Add(new DataColumn("Pro_Name", typeof(string)));
                CartTable.Columns.Add(new DataColumn("Pro_Quantity",typeof(int)));
                CartTable.Columns.Add(new DataColumn("Pro_Price", typeof(decimal)));
                CartTable.Columns.Add(new DataColumn("Pro_SubTotal",typeof(decimal)));
                Session["CartShop"] = CartTable;
            }
            else
            {
                CartTable = (DataTable)Session["CartShop"];
            }
            if (Request.QueryString["proid"].ToString() != null)
            {
                _Pro_Id = Request.QueryString["proid"].ToString();
                InsertList(_Pro_Id);
            }
            gvCartBind();
        }


    }
    /// <summary>
    /// 向DataTable插入数据，并判断是否为同一种商品，如果是则让数量增一，否则创建一行
    /// </summary>
    /// <param name="sPro_Id"></param>
    public void InsertList(string sPro_Id)
    {
        int iPro_Quantity = 1;
        bool IsSame = false;                                      //表示是否为同一种商品
        eWebShop.BLL.Product bPro = new eWebShop.BLL.Product();   //这是购物车的逻辑层

        foreach (DataRow dr in CartTable.Rows)                   //遍历DataTable
        {
            if (dr[0].ToString() == sPro_Id)
            {
                iPro_Quantity = Convert.ToInt32(dr[2].ToString());
                iPro_Quantity++;
                dr[2] = iPro_Quantity;
                dr[4] = iPro_Quantity * Convert.ToDecimal(dr[3].ToString());
                IsSame = true;
            }
        }
        if (!IsSame)                                              //DataTable里没有，则创建一行该商品
        {
            dr = CartTable.NewRow();
            dr[0] = sPro_Id;
            dr[1] = bPro.GetOnlyProductById(sPro_Id).PName;
            dr[2] = iPro_Quantity;
            dr[3] = bPro.GetOnlyProductById(sPro_Id).PMoney;
            dr[4] = iPro_Quantity * Convert.ToDecimal(dr[3].ToString());
            CartTable.Rows.Add(dr);
        }
        Session["CartShop"] = CartTable;                          //添加到Session中

    }
    public void gvCartBind()
    {
        GridView1.DataSource = CartTable;                           //GridView绑定
        GridView1.DataBind();
    }
    /// <summary>
    /// 清空购物车
    /// </summary>
    /// <param name="sender"></param>
    /// <param name="e"></param>
    protected void ImageButton1_Click(object sender, ImageClickEventArgs e)
    {
        Session["CartShop"] = null;
        Response.Write("<script>window.close();</script>");
    }
    /// <summary>
    /// 继续购买商品
    /// </summary>
    /// <param name="sender"></param>
    /// <param name="e"></param>
    protected void ImageButton3_Click(object sender, ImageClickEventArgs e)
    {
        Response.Write("<script>window.close();</script>");
    }
    /// <summary>
    /// 得出商品总的价格
    /// </summary>
    /// <param name="sender"></param>
    /// <param name="e"></param>
    protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e)
    {
        if(e.Row.RowType == DataControlRowType.Footer)
        {
            for (int i = 0; i < CartTable.Rows.Count; i++ )
            {
                dTotal += Convert.ToDouble(CartTable.Rows[i][4]);
            }
        }
    }
    /// <summary>
    /// 调整商品数量并更新DataTable
    /// </summary>
    /// <param name="sender"></param>
    /// <param name="e"></param>
    protected void ImageButton2_Click(object sender, ImageClickEventArgs e)
    {
        CartTable = (DataTable)Session["CartShop"];
        //把GirdView中的数量付给DataTable
        for (int i = 0; i < GridView1.Rows.Count; i++ )
        {
            CartTable.Rows[i][2] = Convert.ToInt32(((TextBox)GridView1.Rows[i].FindControl("txtproquantity")).Text);
        }
        //然后重新遍历DataTable的总的价格
        for (int i = 0; i < CartTable.Rows.Count; i++)
        {
            CartTable.Rows[i][4] = Convert.ToInt32(CartTable.Rows[i][2]) * Convert.ToDecimal(CartTable.Rows[i][3]);
        }
        //GridView重新绑定
        gvCartBind();

    }
    /// <summary>
    /// 下一步，提交
    /// </summary>
    /// <param name="sender"></param>
    /// <param name="e"></param>
    protected void ImageButton4_Click(object sender, ImageClickEventArgs e)
    {
    }
}