1、 将test数据库附加到数据库管理系统中;数据库中的book_info包含下列数据:
2、 新建一个网站,将images文件夹复制到网站中;
3、 在Default.aspx中,通过DataList控件展示数据库中的所有数据,以行为主序,每行3列,单击购买按钮时,将商品的ID和数量保存到HashTable中,并将HashTable放置到Session中。
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protected void DataList1_ItemCommand(object source, DataListCommandEventArgs e)   {     string id = e.CommandArgument.ToString();     Hashtable ht;     if (Session["shopcar"] == null)     {       ht = new Hashtable();       ht.Add(id, 1);       Session["shopcar"] = ht;     }     else    {       ht = (Hashtable)Session["shopcar"];       if (ht.Contains(id))       {         int count = int.Parse(ht[id].ToString());         ht[id] = count + 1;         Session["shopcar"] = ht;         Response.Write(count + 1);       }       else      {         ht.Add(id, 1);         Session["shopcar"] = ht;       }     }   } | 
4、 在Default.aspx中添加一个超链接,链接到shopcart.aspx,在shopcart.aspx中显示用户购买的商品信息。
提示:

A、在shopcart中先定义下列变量:
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Hashtable ht;  DataTable dt;  string connstring=@"DataSource=.\SQLEXPRESS;Initial Catalog=test;Integrated Security=True";  SqlConnection conn;  SqlCommand cmd; SqlDataReader sdr; | 
B、页面中添加一个GridView。
C、在page_load中,将dt实例化,建立各列。
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protected void Page_Load(object sender, EventArgs e)  {    dt = new DataTable();    DataColumn col = new DataColumn();    col.ColumnName= "id";    col.DataType =System.Type.GetType("System.String");    dt.Columns.Add(col);    col = new DataColumn();    col.ColumnName= "name";    col.DataType =System.Type.GetType("System.String");    dt.Columns.Add(col);    col = new DataColumn();    col.ColumnName= "Num";    col.DataType =System.Type.GetType("System.Int32");    dt.Columns.Add(col);    col = new DataColumn();    col.ColumnName= "price";    col.DataType =System.Type.GetType("System.Single");    dt.Columns.Add(col);    col = new DataColumn();    col.ColumnName= "Total";    col.DataType =System.Type.GetType("System.Single");    dt.Columns.Add(col);    if (!IsPostBack)    {      Bind();    }  }      public void Bind()  {           if (Session["shopcar"] == null)    {      Response.Write("<script>if(confirm(‘你没有登录‘)window.location=‘Default15.aspx‘;else window.close();</script>");    }    else    {      ht = (Hashtable)Session["shopcar"];      foreach (object item in ht.Keys)      {        string id = item.ToString();        int num = int.Parse(ht[item].ToString());        string sql = "selectbook_name,price from book_info where book_id=‘" + id + "‘";        conn = new SqlConnection(connstring);        cmd = new SqlCommand(sql, conn);        conn.Open();        sdr =cmd.ExecuteReader();        if (sdr.HasRows)        {          sdr.Read();          DataRow row = dt.NewRow();          row["id"] = id;          row["Num"] = num;          row["name"] = sdr.GetString(0);          row["price"] =float.Parse(sdr[1].ToString());          row["total"] =num*(float.Parse(sdr[1].ToString()));          dt.Rows.Add(row);        }        sdr.Close();        conn.Close();                      }      GridView1.DataSource = dt.DefaultView;      GridView1.DataBind();    }} | 
D、这时可以看到用户购买的商品,但不能修改数量,也不能删除。
E、添加修改数量,删除商品功能,在aspx页面中定义GridView中的各列:
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<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False">    <Columns>      <asp:BoundField DataField="id" HeaderText="ID" />      <asp:BoundField DataField="name" HeaderText="名称" />      <asp:BoundField DataField="price" HeaderText="价格" />      <asp:TemplateField>             <ItemTemplate>        <asp:TextBox runat="server" ID="textbox1" Text=‘<%# Eval("Num") %>‘           ontextchanged="textbox1_TextChanged" AutoPostBack="True" ></asp:TextBox>       </ItemTemplate>            </asp:TemplateField>     <asp:BoundField DataField="total" HeaderText="总计" />     <asp:TemplateField>      <ItemTemplate>       <asp:Button runat="server" ID="button1" CommandArgument=‘<%# Eval("id") %>‘          Text="删除" onclick="button1_Click" />             </ItemTemplate>           </asp:TemplateField>    </Columns>        </asp:GridView> | 
F、为GridView中的文本框添加TextChanged事件:
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protected void textbox1_TextChanged(object sender, EventArgs e)  {         Hashtable ht =(Hashtable)Session["shopcar"];    if (ht == null) return;    for (int i = 0; i < GridView1.Rows.Count;i++)    {      string id =GridView1.Rows[i].Cells[0].Text.ToString();      Response.Write(id);      string num = ((TextBox)GridView1.Rows[i].FindControl("textbox1")).Text;      Response.Write("  "+num+"<br />");      ht[id] = num;    }    Session["shopcar"] = ht;    Bind();      } | 
G、为按钮添加单击事件:
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protected void button1_Click(object sender, EventArgs e)  {    string id = ((Button)sender).CommandArgument;    Hashtable ht = (Hashtable)Session["shopcar"];    if (ht == null) return;    ht.Remove(id);    Bind();} | 
购物车代码:showcart.aspx.cs
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using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.UI; using System.Web.UI.WebControls; using System.Collections; using System.Data; using System.Data.SqlClient;   public partial class shopcart : System.Web.UI.Page {   Hashtable ht;   DataTable dt;   string connstr = "Data Source=.\\SQLEXPRESS;AttachDbFilename=F:\\test.mdf;Integrated Security=True;Connect Timeout=30;User Instance=True";   SqlConnection conn;   SqlCommand cmd;   SqlDataReader sdr;   protected void Page_Load(object sender, EventArgs e)   {     dt = new DataTable();     DataColumn col = new DataColumn();     col.ColumnName = "id";     col.DataType = System.Type.GetType("System.String");     dt.Columns.Add(col);     col = new DataColumn();     col.ColumnName = "name";     col.DataType = System.Type.GetType("System.String");     dt.Columns.Add(col);     col = new DataColumn();     col.ColumnName = "Num";     col.DataType = System.Type.GetType("System.Int32");     dt.Columns.Add(col);     col = new DataColumn();     col.ColumnName = "price";     col.DataType = System.Type.GetType("System.Single");     dt.Columns.Add(col);     col = new DataColumn();     col.ColumnName = "Total";     col.DataType = System.Type.GetType("System.Single");     dt.Columns.Add(col);       if (!IsPostBack)     {       Bind();     }     }     public void Bind()   {     if (Session["shopcar"] == null)     {       Response.Write("<script>if(confirm(‘你没有登录‘)window.location=‘Default.aspx‘;else window.close();</script>");     }     else    {       ht = (Hashtable)Session["shopcar"];       foreach (object item in ht.Keys)       {         string id = item.ToString();           int num = int.Parse((ht[item].ToString()));         string sql = "select book_name,price from book_info where book_id=‘" + id + "‘";         conn = new SqlConnection(connstr);           cmd = new SqlCommand(sql, conn);         conn.Open();           sdr = cmd.ExecuteReader();         if (sdr.HasRows)         {           sdr.Read();           DataRow row = dt.NewRow();           row["id"] = id;           row["Num"] = num;           row["name"] = sdr.GetString(0);           row["price"] = float.Parse(sdr[1].ToString());           row["total"] = num * (float.Parse(sdr[1].ToString()));           dt.Rows.Add(row);           }         sdr.Close();         conn.Close();       }     }     GridView1.DataSource = dt.DefaultView;     GridView1.DataBind();     }   protected void textbox1_TextChanged(object sender, EventArgs e)   {     Hashtable ht = (Hashtable)Session["shopcar"];     if (ht == null) return;     for (int i = 0; i < GridView1.Rows.Count; i++)     {       string id = GridView1.Rows[i].Cells[0].Text.ToString();       Response.Write(id);       string num = ((TextBox)GridView1.Rows[i].FindControl("textbox1")).Text;       Response.Write("  " + num + "<br />");       ht[id] = num;     }     Session["shopcar"] = ht;     Bind();     }   protected void button1_Click(object sender, EventArgs e)   {     string id = ((Button)sender).CommandArgument;     Hashtable ht = (Hashtable)Session["shopcar"];     if (ht == null) return;     ht.Remove(id);     Bind();     } }  | 
制作一个简单的购物车就是这么简单,大家可以按照我的思路进行创作,在此基础上在添加一些功能。
        
