本文实现了c# Session对象实现购物车的方法，分享给大家，也给自己留个笔记：

//shopcart.aspx.cs

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.Data.SqlClient;
using System.Text.RegularExpressions; 

public partial class shopCart : System.Web.UI.Page
{
  CommonClass ccObj = new CommonClass();
  DBClass dbObj = new DBClass();
  string strSql;
  DataTable dtTable;
  Hashtable hashCar;
  protected void Page_Load(object sender, EventArgs e)
  {
    if (!IsPostBack)
    {
      if (Session["ShopCart"] == null)
      {
        //如果没有购物，则给出相应信息，并隐藏按钮
        this.labMessage.Text = "您还没有购物！";
        this.labMessage.Visible = true;    //显示提示信息
        this.lnkbtnCheck.Visible = false;   //隐藏“前往服务台”按钮
        this.lnkbtnClear.Visible = false;   //隐藏“清空购物车”按钮
        this.lnkbtnContinue.Visible = false;  //隐藏“继续购物”按钮

      }
      else
      {
        hashCar = (Hashtable)Session["ShopCart"]; //获取其购物车
        if (hashCar.Count == 0)
        {
          //如果没有购物，则给出相应信息，并隐藏按钮
          this.labMessage.Text = "您购物车中没有商品！";
          this.labMessage.Visible = true;    //显示提示信息
          this.lnkbtnCheck.Visible = false;   //隐藏“前往服务台”按钮
          this.lnkbtnClear.Visible = false;   //隐藏“清空购物车”按钮
          this.lnkbtnContinue.Visible = false;  //隐藏“继续购物”按钮

        }
        else
        {
          //设置购物车内容的数据源
          dtTable = new DataTable();
          DataColumn column1 = new DataColumn("No");    //序号列
          DataColumn column2 = new DataColumn("BookID");  //书籍ID代号
          DataColumn column3 = new DataColumn("BookName"); //书籍名称
          DataColumn column4 = new DataColumn("Num");    //数量
          DataColumn column5 = new DataColumn("price");   //单价
          DataColumn column6 = new DataColumn("totalPrice");//总价
          dtTable.Columns.Add(column1); //添加新列      
          dtTable.Columns.Add(column2);
          dtTable.Columns.Add(column3);
          dtTable.Columns.Add(column4);
          dtTable.Columns.Add(column5);
          dtTable.Columns.Add(column6);
          DataRow row;
          //对数据表中每一行进行遍历，给每一行的新列赋值
          //foreach (object key in hashCar.Keys)
          //{
          //  row = dtTable.NewRow();
          //  row["BookID"] = key.ToString();
          //  row["Num"] = hashCar[key].ToString();
          //  dtTable.Rows.Add(row);
          //}
          foreach (DictionaryEntry hash in hashCar)
          {
            row = dtTable.NewRow();
            row["BookID"] = hash.Key.ToString();
            row["Num"] = hash.Value.ToString();
            dtTable.Rows.Add(row);
          }
          //计算价格
          DataTable dstable;
          int i = 1;
          float price;//商品单价
          int count; //商品数量
          float totalPrice = 0; //商品总价格
          foreach (DataRow drRow in dtTable.Rows)
          {
            strSql = "select BookName,HotPrice from tb_BookInfo where BookID=" + Convert.ToInt32(drRow["BookID"].ToString());
            dstable = dbObj.GetDataSetStr(strSql, "tbGI");
            drRow["No"] = i;//序号
            drRow["BookName"] = dstable.Rows[0][0].ToString();//书籍名称
            drRow["price"] = (dstable.Rows[0][1].ToString());//单价
            price = float.Parse(dstable.Rows[0][1].ToString());//单价
            count = Int32.Parse(drRow["Num"].ToString());
            drRow["totalPrice"] = price * count; //总价
            totalPrice += price * count; //计算合价
            i++;
          }
          this.labTotalPrice.Text = "总价：" + totalPrice.ToString(); //显示所有商品的价格
          this.gvShopCart.DataSource = dtTable.DefaultView;  //绑定GridView控件
          this.gvShopCart.DataKeyNames = new string[] { "BookID" };
          this.gvShopCart.DataBind();
        }
      }
    
    }
    
  }
  public void bind()
  {
    if (Session["ShopCart"] == null)
    {
      //如果没有购物，则给出相应信息，并隐藏按钮
      this.labMessage.Text = "您还没有购物！";
      this.labMessage.Visible = true;    //显示提示信息
      this.lnkbtnCheck.Visible = false;   //隐藏“前往服务台”按钮
      this.lnkbtnClear.Visible = false;   //隐藏“清空购物车”按钮
      this.lnkbtnContinue.Visible = false;  //隐藏“继续购物”按钮
      
    }
    else
    {
      hashCar = (Hashtable)Session["ShopCart"]; //获取其购物车
      if (hashCar.Count == 0)
      {
        //如果没有购物，则给出相应信息，并隐藏按钮
        this.labMessage.Text = "您购物车中没有商品！";
        this.labMessage.Visible = true;    //显示提示信息
        this.lnkbtnCheck.Visible = false;   //隐藏“前往服务台”按钮
        this.lnkbtnClear.Visible = false;   //隐藏“清空购物车”按钮
        this.lnkbtnContinue.Visible = false;  //隐藏“继续购物”按钮
        
      }
      else
      {
        //设置购物车内容的数据源
        dtTable = new DataTable();
        DataColumn column1 = new DataColumn("No");    //序号列
        DataColumn column2 = new DataColumn("BookID");  //书籍ID代号
        DataColumn column3 = new DataColumn("BookName"); //书籍名称
        DataColumn column4 = new DataColumn("Num");    //数量
        DataColumn column5 = new DataColumn("price");   //单价
        DataColumn column6 = new DataColumn("totalPrice");//总价
        dtTable.Columns.Add(column1); //添加新列      
        dtTable.Columns.Add(column2);
        dtTable.Columns.Add(column3);
        dtTable.Columns.Add(column4);
        dtTable.Columns.Add(column5);
        dtTable.Columns.Add(column6);
        DataRow row;
        //对数据表中每一行进行遍历，给每一行的新列赋值
        foreach (object key in hashCar.Keys)
        {
          row = dtTable.NewRow();
          row["BookID"] = key.ToString();
          row["Num"] = hashCar[key].ToString();
          dtTable.Rows.Add(row);
        }
        //计算价格
        DataTable dstable;
        int i = 1;
        float price;//商品单价
        int count; //商品数量
        float totalPrice = 0; //商品总价格
        foreach (DataRow drRow in dtTable.Rows)
        {
          strSql = "select BookName,HotPrice from tb_BookInfo where BookID=" + Convert.ToInt32(drRow["BookID"].ToString());
          dstable = dbObj.GetDataSetStr(strSql, "tbGI");
          drRow["No"] = i;//序号
          drRow["BookName"] = dstable.Rows[0][0].ToString();//书籍名称
          drRow["price"] = (dstable.Rows[0][1].ToString());//单价
          price = float.Parse(dstable.Rows[0][1].ToString());//单价
          count = Int32.Parse(drRow["Num"].ToString());
          drRow["totalPrice"] = price * count; //总价
          totalPrice += price * count; //计算合价
          i++;
        }
        this.labTotalPrice.Text = "总价：" + totalPrice.ToString(); //显示所有商品的价格
        this.gvShopCart.DataSource = dtTable.DefaultView;  //绑定GridView控件
        this.gvShopCart.DataKeyNames=new string[] {"BookID"};
        this.gvShopCart.DataBind();
      }
    }
      
  
  
  }
  protected void lnkbtnUpdate_Click(object sender, EventArgs e)
  {
    hashCar = (Hashtable)Session["ShopCart"]; //获取其购物车
    //使用foreach语句，遍历更新购物车中的商品数量
    foreach (GridViewRow gvr in this.gvShopCart.Rows)
    {
      TextBox otb = (TextBox)gvr.FindControl("txtNum"); //找到用来输入数量的TextBox控件 
      int count = Int32.Parse(otb.Text);//获得用户输入的数量值
      string BookID = gvr.Cells[1].Text;//得到该商品的ID代
      hashCar[BookID] = count;//更新hashTable表
    }
    Session["ShopCart"] = hashCar;//更新购物车
    Response.Redirect("shopCart.aspx");
  }
  protected void lnkbtnDelete_Command(object sender, CommandEventArgs e)
  {
    hashCar = (Hashtable)Session["ShopCart"];//获取其购物车
    //从Hashtable表中，将指定的商品从购物车中移除，其中，删除按钮(lnkbtnDelete)的CommandArgument参数值为商品ID代号
    hashCar.Remove(e.CommandArgument);
    Session["ShopCart"] = hashCar; //更新购物车
    Response.Redirect("shopCart.aspx");
  }
  protected void lnkbtnClear_Click(object sender, EventArgs e)
  {
    Session["ShopCart"] =null;
    Response.Redirect("shopCart.aspx");
  }
  protected void lnkbtnContinue_Click(object sender, EventArgs e)
  {
    Response.Redirect("Default.aspx");
  }
  protected void lnkbtnCheck_Click(object sender, EventArgs e)
  {
    Response.Redirect("checkOut.aspx");
  }
  protected void gvShopCart_PageIndexChanging(object sender, GridViewPageEventArgs e)
  {
    gvShopCart.PageIndex = e.NewPageIndex;
    bind();

  }
  protected void txtNum_TextChanged(object sender, EventArgs e)
  {
    hashCar = (Hashtable)Session["ShopCart"]; //获取其购物车
    foreach (GridViewRow gvr in this.gvShopCart.Rows)
    {

      TextBox otb = (TextBox)gvr.FindControl("txtNum"); //找到用来输入数量的TextBox控件 
      int count = Int32.Parse(otb.Text);//获得用户输入的数量值
      string BookID = gvr.Cells[1].Text;//得到该商品的ID代
      hashCar[BookID] = count;//更新hashTable表

    }
    Session["ShopCart"] = hashCar;//更新购物车
    bind();

  }