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使用hashtable实现的购物车

2004-12-02 18:57 513 查看

在网上看到一些都不太好理解，所以把它们结合了一下，用HashTable去保存商品，再用DataTable写入到Datagrid中。http://61.180.163.222/shop

<%@ Page Language="VB" ContentType="text/html" Debug="true"%>
<%@ import namespace="system.data" %>
<%@ import namespace="system.data.oledb" %>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<title>无标题文档</title>
<style type="text/css">

</style>
<style type="text/css">

</style>
</head>
<body leftmargin="0" topmargin="0" marginwidth="0" marginheight="0">
<form runat="server">

<table width="776" border="0" cellspacing="0" cellpadding="0">
<tr>
    <td width="159"> </td>
    <td width="617"><table width="100%" border="0" cellspacing="0" cellpadding="0">
        <tr>
          <td width="17%" height="26"><p> </p>
              <p>您所选购的商品</p></td>
          <td width="2%" height="26"> </td>
          <td width="81%" height="26"> </td>
        </tr>
        <tr>
          <td height="26"> </td>
          <td height="26"> </td>
          <td height="26"><asp:Datagrid ID="dgCar" runat="server"
                                              autogeneratecolumns="false"
                                                                      BorderColor="#000000"
                                                                      BorderWidth="1"
                                                                      CellPadding="3"
                                                                      HeaderStyle-BackColor="#990000"
                                                                      HeaderStyle-ForeColor="#FFFFFF"
                                                                   DataKeyField="title_id"
                                                                      >
                                                     <columns>
                                                               <asp:boundcolumn HeaderText="商品" DataField="title" ItemStyle-Width="300"></asp:boundcolumn>
                                                               <asp:templatecolumn HeaderText="数量">
                                                                      <itemtemplate>
                                                                             <asp:textbox size=1 id="Qty" runat="server"
                                                                             text='<%# Databinder.eval(container.dataitem,"qty")%>'/>
                                                                      </itemtemplate>
                                                               </asp:templatecolumn>
                                                               <asp:boundcolumn HeaderText="单价" DataField="price" DataFormatString="{0:c}"></asp:boundcolumn>
                                                               <asp:boundcolumn HeaderText="总计" DataField="total" DataFormatString="{0:c}"></asp:boundcolumn>
                                                               <asp:templatecolumn HeaderText="删除">
                                                                      <itemtemplate>
                                                                             <asp:checkbox runat="server" ID="del"/>
                                                                      </itemtemplate>
                                                               </asp:templatecolumn>
                                                        </columns>
                                         </asp:Datagrid>
                                          <asp:label runat="server" ID="msg" text="购物车为空" />
              <hr>
              <div align="right">总计:
                <asp:label ID="lbltotal" runat="server" text="0"></asp:label>
                <br>
                折扣:<asp:label ID="sale" runat="server" Text="0.9"></asp:label><br>
                应付:<asp:label ID="realprice" runat="server" Text="0" /></div>
              <div align="center"><br>
                <asp:imagebutton ID="re_car" ImageUrl="images/cxjs.gif" runat="server" OnClick="re_car_click" />
                <asp:imagebutton ID="buy" ImageUrl="images/qsyt.gif" runat="server" />
                <asp:imagebutton ID="clear" ImageUrl="images/qk.gif" runat="server" OnClick="clear_click" />
                <a href="display_all.aspx">继续购物</a></div></td>
        </tr>
        <tr>
          <td height="26"> </td>
          <td height="26"> </td>
          <td height="26"> </td>
        </tr>
      </table></td>
</tr>
</table>
<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />


</form>
</body>
</html>
<script runat="server">
Sub Page_Load(Src As Object, E As EventArgs)
if not ispostback then
       '取得用户要加入购物书的商品的ID
       Dim product as string = request.QueryString("title-id")
       '判断如果是用户所购买的第一件商品的话则那立一个hashTable
       '否则从session中将已经存在的hashTable取回
       Dim Hash As HashTable
       IF Session("car") is nothing then
              hash = New hashTable
       Else
              Hash = Session("car")
       End if
       '判断用户所选购的商品是否已经存在于购物车中
       '如果不存在则将其加入购物车，如果存在则在原有数据上加1
       if Not Hash.ContainsKey(product) then
              Hash.Add(product,1)
       else
              hash.item(product) +=1
       end if
       session("car")=hash
       display()
end if
End Sub
'------------------用于显示商品的子程序--------------------
Sub Display()
       Dim i as integer
       dim x as string

       '取得session中的hashTable
       dim hash as hashtable
       Hash = Session("car")

       '将所有选购的商品构造成为一个字符串
       dim Products As String
       products = "('"
       For Each X in hash.keys
              Products = products & X & "','"
       next
       Products = Products & "')"

       '根据所购商品的字符串读取商品信息,然后放在producttable中
       dim conn as oledbconnection
       Dim ds as new dataset
       dim Table1 as DataTable
       dim connstr as string = "provider=Microsoft.jet.oledb.4.0;data source=" & server.MapPath("db3.mdb")
       conn = new oledbconnection(connstr)
       conn.open()

       '读取数据并将数据填充到table1中
       dim comm as oledbdataadapter
       dim strsql as string ="select title_id,title,price from titles where title_id in " & products
       comm = new oledbdataadapter(strsql,conn)
       comm.fill(ds,"product")
       table1 = ds.tables("product")

       '向table1中增加一列
       table1.columns.add(new datacolumn("qty",gettype(integer)))

       '将title设置为主键
       Dim Keys() as DataColumn = {table1.Columns("title_id")}
       table1.primarykey=keys

       '向producttable表新增字段
       for each x in hash.keys
              table1.rows.find(x).item("qty")=hash.item(x)
       next

       '向table1中增加总计列,并计算总计值
       table1.columns.add(new datacolumn("total",gettype(double),"price*qty"))

       '判断购物车是否为空
       if table1.rows.count =0 then
              dgcar.visible="false"
              msg.visible="true"
       else
              dgcar.visible="True"
              msg.visible="False"
       end if

       '计算帐单总价及折扣后的价格
       lbltotal.text="0"
       For i=0 to table1.rows.count-1
              lbltotal.text =string.format("{0:c}",cdbl(lbltotal.text)+table1.rows(i).item("total"))
       next
       realprice.text = string.format("{0:c}",cdbl(sale.text) * lbltotal.text)
       '将数据绑定dgcar
       dgCar.datasource=table1.defaultview
       dgCar.databind()
       conn.close
End Sub
'------------------用于清空购物车的事件程序---------------
Sub clear_click(sender as object,e as imageclickeventargs)
       '将session("car")清空
       session("car") = new hashtable()
       lbltotal.text = "0"
       realprice.text="0"
       display()
End sub
'------------------用于更新购物车的事件程序------------------
Sub re_car_click(sender as object,e as imageclickeventargs)
       '判断Session("car")是否存在，如果在刚将其取得保存在hash中
       Dim Hash As HashTable
       IF Session("car") is nothing then
              hash = New hashTable
       Else
              Hash = Session("car")
       End if
       '依决检查每一行的数量和checkbox控件，并更新hashtable
       Dim qty As Textbox
       dim del as checkbox
       Dim I as integer
       For I = 0 to dgcar.items.count -1
              qty = dgcar.items(i).findcontrol("qty")
              del = dgcar.items(i).findcontrol("del")
              if (cint(qty.text)> 0) and (not del.checked) then
                     hash(dgcar.datakeys(i))=cint(qty.text)
              else
                     hash.remove(dgcar.datakeys(i))
              end if
       next
       display()
End sub
</script>

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标签： session table asp datagrid server integer

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