[ASP.NET开发系列] 购物推车程序开发——调用购物车类
上一篇《购物推车程序开发——调用购物车类》文件定义和部署了一个购物车类（ShoppingCart.cs），其中AddItem（）和DeleteItem（）两个方法分别完成了商品的添加和删除功能。这一篇文章着重如何在ASPX文件里调用该购物车类，使用C#语言编写。
Default.aspx
<%@ Import Namespace="WendwCart"%>
<%@ Import Namespace="System.Data"%>
<%@ Import Namespace="System.Data.SqlClient"%>
<html>
<body>
<form runat="server">
<table width="100%">
<tr>
<td><asp:Button Text="查看" OnClick=" View_ShoppingCart " runat="server"/></td>
</tr>
</table>
<br>
<center>
<asp:DataGrid ID="MyDataGrid"
AutoGenerateColumns="false" Cellpadding="2"
BorderWidth="1" BorderColor="lightgray"
Font-Name="Verdana" Font-Size="10pt"
GridLines="vertical" Width="90%"
OnItemCommand="OnItemCommand" runat="server">
<columns>
<asp:BoundColumn HeaderText="商品ID" DataField="ItemID"/>
<asp:BoundColumn headerText="名 称" DataField=" ShangpinName "
headerStyle-HorizontalAlign="center"/>
<asp:BoundColumn HeaderText="价 格" DataField="Price"
DataFormatString="{0:c}" headerStyle-HorizontalAlign="center"
ItemStyle-HorizontalAlign="right"/>
<asp:ButtonColumn HeaderText="订 购" Text="加入购物车"
headerStyle-HorizontalAlign="center"
ItemStyle-HorizontalAlign="center" CommandName="AddToCart"/>
</columns>
<HeaderStyle BackColor="teal" ForeColor="white" Font-Bold="true"/>
<ItemStyle BackColor="white" ForeColor="darkblue"/>
<AlternatingItemStyle BackColor="beige" ForeColor="darkblue"/>
</asp:DataGrid>
</center>
</form>
</body>
</html>
//连接数据库绑定数据到DataGrid控件
<script Language="C#" runat="server">
void Page_Load(Object sender,EventArgs e){
if(!IsPostBack){
String ConnectString=ConfigurationSettings.AppSettings["DataConnectionString"];
SqlDataAdapter adapter=new SqlDataAdapter("select * from Tb_ShangPin where sp_Price!=0",ConnectString);
DataSet ds=new DataSet();
adapter.Fill(ds);
MyDataGrid.DataSource=ds;
MyDataGrid.DataBind();
}
}
//添加商品
void OnItemCommand(Object sender,DataGridCommandEventArgs e){
if(e.CommandName=="AddToCart"){
Stat_Class order=new Stat_Class (e.Item.Cells[0].Text,e.Item.Cells[1].Text,Convert.ToDecimal(e.Item.Cells[2].Text.Substring(1)),1);
ShoppingCart cart=(ShoppingCart)Session["MyShoppingCart"]; //创建实例
if(cart!=null)
cart.AddItem(order);
}
}
//查看购物车,通过Response.Redirect()转到View_ShoppingCart.aspx页面
void View_ShoppingCart(Object sender,EventArgs e)
{
Response.Redirect("View_ShoppingCart.aspx");
}
</script>
说明：本例使用到数据库，在运行程序之前，我们先创建一个数据库和表，分别取名为Test_Db和Tb_ShangPin。表Tb_ShangPin有很多字段，其中包含sp_id、sp_Name、sp_Price几个字段。接下来我们把连接数据库的字符串写进web.config文件里，代码如下：
<configuration>
<appSettings>
<add key="DataConnectionString" value="server=(local);database=Test_Db;Trusted_Connection=no;uid=sa;pwd=1234"/>
</appSettings>
</configuration>
查看购物车程序View_ShoppingCart.aspx
<%@ Import Namespace="WendwCart"%>
<html>
<body>
<form runat="server">
<table width="100%">
<tr>
<td>
<asp:Button Text="继续购物" OnClick="Gonoshopping" runat="server"/>
</td>
</tr>
</table>
<br>
<center>
<asp:DataGrid ID="MyDataGrid"
AutoGenerateColumns="false"
Cellpadding="2"
BorderWidth="1"
BorderColor="lightgray"
Font-Name="Verdana"
Font-Size="10pt"
GridLines="Vertical"
Width="90%"
OnItemCommand="OnItemCommand"
runat="server">
<columns>
<asp:BoundColumn HeaderText="图书ID" DataField="ItemID"/>
<asp:BoundColumn headerText="书 名" DataField=" ShangpinName "/>
<asp:BoundColumn HeaderText="价 格" DataField="Price"
DataFormatString="{0:c}" headerStyle-HorizontalAlign="center"
ItemStyle-HorizontalAlign="right"/>
<asp:BoundColumn HeaderText="数量" DataField="Quantity"
headerStyle-HorizontalAlign="center"
ItemStyle-HorizontalAlign="center"/>
<asp:ButtonColumn HeaderText="删除" Text="删除"
headerStyle-HorizontalAlign="center"
ItemStyle-HorizontalAlign="center" CommandName="DelFromCart"/>
</columns>
<HeaderStyle BackColor="teal" ForeColor="white" Font-Bold="true"/>
<ItemStyle BackColor="white" ForeColor="darkblue"/>
<AlternatingItemStyle BackColor="beige" ForeColor="darkblue"/>
</asp:DataGrid>
</center>
<h3><asp:Label ID="Total" runat="server"/></h3>
</form>
</body>
</html>
<script Language="C#" runat="server">
void Page_Load(Object sender,EventArgs e){
ShoppingCart cart=(ShoppingCart)Session["MyShoppingCart"]; //创建实例
if(cart !=null){
MyDataGrid.DataSource=cart.Orders;
MyDataGrid.DataBind();
Total.Text=String.Format("合计:{0:c}",cart.TotalCost);
}
}
void OnItemCommand(Object sender,DataGridCommandEventArgs e){
if(e.CommandName=="DelFromCart"){
ShoppingCart cart=(ShoppingCart)Session["MyShoppingCart"];
if(cart != null){
cart.DeleteItem(e.Item.Cells[0].Text);
MyDataGrid.DataBind();
Total.Text=String.Format("合计:{0:c}",cart.TotalCost);
}
}
}
public void Gonoshopping(Object sender,EventArgs e)
{
Response.Redirect("default.aspx");
}
</script>
总结：这两篇文章只是简单的介绍一下购物推车的基本原理，要应用到实际项目中还需要做很多工作。
