如何利用Session對象實現購物車

這篇文章主要介紹如何利用Session對象實現購物車，文中介紹的非常詳細，具有一定的參考價值，感興趣的小伙伴們一定要看完！

//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)
            {
                //如果沒有購物，則給出相應信息，并隱藏按鈕
                this.labMessage.Text = "您還沒有購物！";
                this.labMessage.Visible = true;        //顯示提示信息
                this.lnkbtnCheck.Visible = false;      //隱藏“前往服務臺”按鈕
                this.lnkbtnClear.Visible = false;      //隱藏“清空購物車”按鈕
                this.lnkbtnContinue.Visible = false;   //隱藏“繼續購物”按鈕

            }
            else
            {
                hashCar = (Hashtable)Session["ShopCart"]; //獲取其購物車
                if (hashCar.Count == 0)
                {
                    //如果沒有購物，則給出相應信息，并隱藏按鈕
                    this.labMessage.Text = "您購物車中沒有商品！";
                    this.labMessage.Visible = true;        //顯示提示信息
                    this.lnkbtnCheck.Visible = false;      //隱藏“前往服務臺”按鈕
                    this.lnkbtnClear.Visible = false;      //隱藏“清空購物車”按鈕
                    this.lnkbtnContinue.Visible = false;   //隱藏“繼續購物”按鈕

                }
                else
                {
                    //設置購物車內容的數據源
                    dtTable = new DataTable();
                    DataColumn column1 = new DataColumn("No");        //序號列
                    DataColumn column2 = new DataColumn("BookID");    //書籍ID代號
                    DataColumn column3 = new DataColumn("BookName");  //書籍名稱
                    DataColumn column4 = new DataColumn("Num");       //數量
                    DataColumn column5 = new DataColumn("price");     //單價
                    DataColumn column6 = new DataColumn("totalPrice");//總價
                    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;
                    //對數據表中每一行進行遍歷，給每一行的新列賦值
                    //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);
                    }
                    //計算價格
                    DataTable dstable;
                    int i = 1;
                    float price;//商品單價
                    int count;  //商品數量
                    float totalPrice = 0; //商品總價格
                    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;//序號
                        drRow["BookName"] = dstable.Rows[0][0].ToString();//書籍名稱
                        drRow["price"] = (dstable.Rows[0][1].ToString());//單價
                        price = float.Parse(dstable.Rows[0][1].ToString());//單價
                        count = Int32.Parse(drRow["Num"].ToString());
                        drRow["totalPrice"] = price * count; //總價
                        totalPrice += price * count; //計算合價
                        i++;
                    }
                    this.labTotalPrice.Text = "總價：" + totalPrice.ToString();  //顯示所有商品的價格
                    this.gvShopCart.DataSource = dtTable.DefaultView;   //綁定GridView控件
                    this.gvShopCart.DataKeyNames = new string[] { "BookID" };
                    this.gvShopCart.DataBind();
                }
            }

        }

    }
    public void bind()
    {
        if (Session["ShopCart"] == null)
        {
            //如果沒有購物，則給出相應信息，并隱藏按鈕
            this.labMessage.Text = "您還沒有購物！";
            this.labMessage.Visible = true;        //顯示提示信息
            this.lnkbtnCheck.Visible = false;      //隱藏“前往服務臺”按鈕
            this.lnkbtnClear.Visible = false;      //隱藏“清空購物車”按鈕
            this.lnkbtnContinue.Visible = false;   //隱藏“繼續購物”按鈕

        }
        else
        {
            hashCar = (Hashtable)Session["ShopCart"]; //獲取其購物車
            if (hashCar.Count == 0)
            {
                //如果沒有購物，則給出相應信息，并隱藏按鈕
                this.labMessage.Text = "您購物車中沒有商品！";
                this.labMessage.Visible = true;        //顯示提示信息
                this.lnkbtnCheck.Visible = false;      //隱藏“前往服務臺”按鈕
                this.lnkbtnClear.Visible = false;      //隱藏“清空購物車”按鈕
                this.lnkbtnContinue.Visible = false;   //隱藏“繼續購物”按鈕

            }
            else
            {
                //設置購物車內容的數據源
                dtTable = new DataTable();
                DataColumn column1 = new DataColumn("No");        //序號列
                DataColumn column2 = new DataColumn("BookID");    //書籍ID代號
                DataColumn column3 = new DataColumn("BookName");  //書籍名稱
                DataColumn column4 = new DataColumn("Num");       //數量
                DataColumn column5 = new DataColumn("price");     //單價
                DataColumn column6 = new DataColumn("totalPrice");//總價
                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;
                //對數據表中每一行進行遍歷，給每一行的新列賦值
                foreach (object key in hashCar.Keys)
                {
                    row = dtTable.NewRow();
                    row["BookID"] = key.ToString();
                    row["Num"] = hashCar[key].ToString();
                    dtTable.Rows.Add(row);
                }
                //計算價格
                DataTable dstable;
                int i = 1;
                float price;//商品單價
                int count;  //商品數量
                float totalPrice = 0; //商品總價格
                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;//序號
                    drRow["BookName"] = dstable.Rows[0][0].ToString();//書籍名稱
                    drRow["price"] = (dstable.Rows[0][1].ToString());//單價
                    price = float.Parse(dstable.Rows[0][1].ToString());//單價
                    count = Int32.Parse(drRow["Num"].ToString());
                    drRow["totalPrice"] = price * count; //總價
                    totalPrice += price * count; //計算合價
                    i++;
                }
                this.labTotalPrice.Text = "總價：" + totalPrice.ToString();  //顯示所有商品的價格
                this.gvShopCart.DataSource = dtTable.DefaultView;   //綁定GridView控件
                this.gvShopCart.DataKeyNames=new string[] {"BookID"};
                this.gvShopCart.DataBind();
            }
        }

    }
    protected void lnkbtnUpdate_Click(object sender, EventArgs e)
    {
        hashCar = (Hashtable)Session["ShopCart"];  //獲取其購物車
        //使用foreach語句，遍歷更新購物車中的商品數量
        foreach (GridViewRow gvr in this.gvShopCart.Rows)
        {
            TextBox otb = (TextBox)gvr.FindControl("txtNum"); //找到用來輸入數量的TextBox控件 
            int count = Int32.Parse(otb.Text);//獲得用戶輸入的數量值
            string BookID = gvr.Cells[1].Text;//得到該商品的ID代
            hashCar[BookID] = count;//更新hashTable表
        }
        Session["ShopCart"] = hashCar;//更新購物車
        Response.Redirect("shopCart.aspx");
    }
    protected void lnkbtnDelete_Command(object sender, CommandEventArgs e)
    {
        hashCar = (Hashtable)Session["ShopCart"];//獲取其購物車
        //從Hashtable表中，將指定的商品從購物車中移除，其中，刪除按鈕(lnkbtnDelete)的CommandArgument參數值為商品ID代號
        hashCar.Remove(e.CommandArgument);
        Session["ShopCart"] = hashCar; //更新購物車
        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"];  //獲取其購物車
        foreach (GridViewRow gvr in this.gvShopCart.Rows)
        {

            TextBox otb = (TextBox)gvr.FindControl("txtNum"); //找到用來輸入數量的TextBox控件 
            int count = Int32.Parse(otb.Text);//獲得用戶輸入的數量值
            string BookID = gvr.Cells[1].Text;//得到該商品的ID代
            hashCar[BookID] = count;//更新hashTable表

        }
        Session["ShopCart"] = hashCar;//更新購物車
        bind();

    }

//shopcart.aspx

                        <table cellSpacing="0" cellPadding="0" width="95%" align="center" border="0" >
                             <tr>
                             <td align="center">
                                <asp:Label ID="labMessage" runat="server" Visible="False"></asp:Label></td>
                            </tr>
                            <tr>
                             <td align="left" height =30px>
                                <asp:Label ID="labTotalPrice" runat="server" Text="0.00 " ></asp:Label>￥</td>
                            </tr>
                            <tr style =" font :9pt; font-family :宋體;"  valign =top >
                            <td align="left" >

                             <asp:GridView ID="gvShopCart" DataKeyNames ="BookID"   runat="server"  AutoGenerateColumns="False"  AllowPaging="True" OnPageIndexChanging="gvShopCart_PageIndexChanging" >
                                 <Columns>
                                     <asp:BoundField DataField="No" HeaderText="序號" ReadOnly="True">
                                         <ItemStyle HorizontalAlign="Center" />
                                         <HeaderStyle HorizontalAlign="Center" />
                                     </asp:BoundField>  
                                      <asp:BoundField DataField="BookID" HeaderText="書籍ID" ReadOnly="True">
                                         <ItemStyle HorizontalAlign="Center" />
                                         <HeaderStyle HorizontalAlign="Center" />
                                     </asp:BoundField>                                    
                                     <asp:BoundField DataField="BookName" HeaderText="書籍名稱" ReadOnly="True">
                                      <ItemStyle HorizontalAlign="Center" />
                                      <HeaderStyle HorizontalAlign="Center" />
                                     </asp:BoundField>  
                                     <asp:TemplateField HeaderText="數量">
                                    <ItemTemplate >
                                       <asp:TextBox ID="txtNum" runat="server" Text =<%#Eval("Num") %> Width =60px  OnTextChanged="txtNum_TextChanged"></asp:TextBox>
                                       <asp:RegularExpressionValidator
                                ID="RegularExpressionValidator1" runat="server" ControlToValidate="txtNum"
                                ErrorMessage="×" ValidationExpression="^\+?[1-9][0-9]*$"></asp:RegularExpressionValidator>
                                </ItemTemplate>
                                </asp:TemplateField>

                                     <asp:TemplateField HeaderText =單價>
                                         <HeaderStyle HorizontalAlign=Center />
                                         <ItemStyle HorizontalAlign =Center />
                                         <ItemTemplate >
                                            <%#Eval("price")%>￥
                                         </ItemTemplate>    
                                     </asp:TemplateField>
                                    <asp:TemplateField HeaderText =總價>
                                         <HeaderStyle HorizontalAlign=Center />
                                         <ItemStyle HorizontalAlign =Center />
                                         <ItemTemplate >
                                            <%#Eval("totalPrice")%>￥
                                         </ItemTemplate>    
                                     </asp:TemplateField>
                                     <asp:TemplateField>
                                         <HeaderStyle HorizontalAlign=Center />
                                         <ItemStyle HorizontalAlign =Center />
                                         <ItemTemplate >
                                             <asp:LinkButton ID="lnkbtnDelete" runat="server" CommandArgument ='<%#Eval("BookID") %>' OnCommand ="lnkbtnDelete_Command">刪除</asp:LinkButton>
                                         </ItemTemplate>    
                                     </asp:TemplateField>

                                 </Columns>
                                </asp:GridView>
                            </td>
                            </tr>
                            <tr align =left valign =top  >
                                <td align="center"  >
                                    <asp:LinkButton ID="lnkbtnUpdate" runat="server" OnClick="lnkbtnUpdate_Click">更新購物車</asp:LinkButton>
                                    &nbsp;<asp:LinkButton ID="lnkbtnClear" runat="server" OnClick="lnkbtnClear_Click" >清空購物車</asp:LinkButton>
                                    <asp:LinkButton ID="lnkbtnContinue" runat="server" OnClick="lnkbtnContinue_Click" >繼續購物</asp:LinkButton>  
                                    <asp:LinkButton ID="lnkbtnCheck" runat="server" OnClick="lnkbtnCheck_Click" >前往服務臺</asp:LinkButton>
                                    </td>
                            </tr>
                            <tr>
                            <td align="left"  >
                                <br />
                                &nbsp;<li>如果要修改商品數量，請單擊“更新購物車”按鈕 &nbsp;&nbsp;&nbsp;</li>&nbsp;<li>如果要取消某個商品，請單擊“刪除”
                            <br />
                            </li>
                            </td>
                            </tr>
                        </table>

Default.aspx.cs //添加物品到購物車代碼

    protected void dlDiscount_ItemCommand(object source, DataListCommandEventArgs e)
    {
        if (e.CommandName == "detailSee")
        {
            AddressBack(e);
        }
        else if (e.CommandName == "buy")
        {
            AddShopCart(e);
        } 

    }
    protected void dlHot_ItemCommand(object source, DataListCommandEventArgs e)
    {
        if (e.CommandName == "detailSee")
        {
            AddressBack(e);
        }
        else if (e.CommandName == "buy")
        {
            AddShopCart(e);
        }

    }
    /// <summary>
    /// 向購物車中添加新商品
    /// </summary>
    /// <param name="e">
    /// 獲取或設置可選參數，
    /// 該參數與關聯的 CommandName 
    /// 一起被傳遞到 Command 事件。
    /// </param> 
    public void AddShopCart(DataListCommandEventArgs e)
    {
        Hashtable hashCar;
        if (Session["ShopCart"] == null)
        {
            //如果用戶沒有分配購物車
            hashCar = new Hashtable();         //新生成一個
            hashCar.Add(e.CommandArgument, 1); //添加一個商品
            Session["ShopCart"] = hashCar;     //分配給用戶
        }
        else
        {
            //用戶已經有購物車
            hashCar = (Hashtable)Session["ShopCart"];//得到購物車的hash表
            if (hashCar.Contains(e.CommandArgument))//購物車中已有此商品，商品數量加1
            {
                int count = Convert.ToInt32(hashCar[e.CommandArgument].ToString());//得到該商品的數量
                hashCar[e.CommandArgument] = (count + 1);//商品數量加1
            }
            else
                hashCar.Add(e.CommandArgument, 1);//如果沒有此商品，則新添加一個項
        }

    }

this.ClientScript.RegisterStartupScript(this.GetType(),"",<script>alert("商品添加成功!")</script>);

另附上一關于session實現購物車的視頻講解地址：http://www.itzcn.com/video-vid-251-spid-19.html

HashTable實現購物車， 

  先前我們的購物車使用的是數據庫方式實現，每次購物都要進行數據庫操作，很影響效率。現在我們采用HashTable和Session來實現購物車，這樣便節省了數據庫的操作，大大的提高效率 

1 private void DataGrid1_ItemCommand(object source, System.Web.UI.WebControls.DataGridCommandEventArgs e)//假設前面購買命令是一個命令名為buy的LinkButton
   2 {//關鍵，建立和加如購物車
   3 string pid=this.DataGrid1.DataKeys[e.Item.ItemIndex].ToString();//取出編號
   4 if(e.CommandName=="buy")//如果命令名是 buy，說明是購買
   5 {
6 if(Session["bus"]==null)//先就得檢查購物車是否存在,如果不存在,就建立 
   7 {
8 System.Collections.Hashtable ht=new Hashtable();//先建立一個哈希表
   9 ht.Add(pid,1);//哈希表中的兩個列，一個key，一個value ，key放編號，value放購買數量好了，預設置為１
  10 Session["bus"]=ht;//將哈希表賦值給Session對象
  11 }
12 else//如果存在的話
  13 {
14 Hashtable ht=(Hashtable)Session["bus"];//使用強制類型轉換，再將Session["bus"]賦值給哈希表對象 ht
  15 if(ht[pid]==null)//如果哈希表中對應的ＩＤ沒有，
  16 {
17 ht[pid]=1;//那就直接給他設為　１
  18 }
19 else//如果已經有對應的ＩＤ
  20 {
21 ht[pid]=(int)ht[pid]+1;//那么就把原來的取出來再加上　１
  22 }
23 Session["bus"]=ht;//最后再更新Session 對象
  24 }
25 }
26
27 } 

  而讀取的方法如下: 

this.DataList1.DataSource=(Hashtable)Session["bus"];
this.DataList1.DataBind();
1private void LinkButton1_Click(object sender, System.EventArgs e)
2 {
3
4 foreach(DataListItem dl in this.DataList1.Items)//遍歷集合
5 {
6 TextBox tb=(TextBox)dl.FindControl("TextBox1");//找到文本框
7 int newpid=Convert.ToInt32(tb.Text.ToString());//查出文本框里面的值
8
9 Label label1=(Label)dl.FindControl("key");//找到裝載哈希表key字段的那個控件
10 string pid=label1.Text.ToString();//把他的值拿出來
11
12 Hashtable ht=(Hashtable)Session["bus"];//把session["bus"]對象賦值給哈希表 ht
13 int oldpid=(int)ht[pid];//求得原來的數量
14
15 if(newpid!=oldpid)//如果文本框里的值不等于原來的數量，就用新的更換到哈希表中的值
16 {
17 ht[pid]=newpid;
18 }
19 Session["bus"]=ht;//最后再更新Session 對象
20 }
21 }

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