1.A,运行效果图 
1.B,源代码
复制代码代码如下:
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="DropLvw.aspx.cs" Inherits="DropLvw" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title>无标题页</title>
</head>
<body>
<form id="form1" runat="server">
<div>
请选择大分类：<asp:DropDownList ID="drop" runat="server" AutoPostBack="True"
DataSourceID="SqlDataSource1" DataTextField="CategoryName"
DataValueField="CategoryID">
</asp:DropDownList>
<asp:SqlDataSource ID="SqlDataSource1" runat="server"
ConnectionString="<%$ ConnectionStrings:NorthwindConnectionString %>"
SelectCommand="SELECT [CategoryID], [CategoryName] FROM [Categories]">
</asp:SqlDataSource>
<hr />
该分类下的产品：<br />
<asp:ListView ID="lvw" runat="server" DataKeyNames="ProductID"
DataSourceID="SqlDataSource2">
<ItemTemplate>
<tr style="">
<td>
<asp:Label ID="ProductIDLabel" runat="server" Text='<%# Eval("ProductID") %>' />
</td>
<td>
<asp:Label ID="ProductNameLabel" runat="server"
Text='<%# Eval("ProductName") %>' />
</td>
<td>
<asp:Label ID="CategoryIDLabel" runat="server"
Text='<%# Eval("CategoryID") %>' />
</td>
<td>
<asp:Label ID="UnitPriceLabel" runat="server" Text='<%# Eval("UnitPrice") %>' />
</td>
</tr>
</ItemTemplate>
<AlternatingItemTemplate>
<tr style="">
<td>
<asp:Label ID="ProductIDLabel" runat="server" Text='<%# Eval("ProductID") %>' />
</td>
<td>
<asp:Label ID="ProductNameLabel" runat="server"
Text='<%# Eval("ProductName") %>' />
</td>
<td>
<asp:Label ID="CategoryIDLabel" runat="server"
Text='<%# Eval("CategoryID") %>' />
</td>
<td>
<asp:Label ID="UnitPriceLabel" runat="server" Text='<%# Eval("UnitPrice") %>' />
</td>
</tr>
</AlternatingItemTemplate>
<EmptyDataTemplate>
<table runat="server" style="">
<tr>
<td>
未返回数据。</td>
</tr>
</table>
</EmptyDataTemplate>
<InsertItemTemplate>
<tr style="">
<td>
<asp:Button ID="InsertButton" runat="server" CommandName="Insert" Text="插入" />
<asp:Button ID="CancelButton" runat="server" CommandName="Cancel" Text="清除" />
</td>
<td>
</td>
<td>
<asp:TextBox ID="ProductNameTextBox" runat="server"
Text='<%# Bind("ProductName") %>' />
</td>
<td>
<asp:TextBox ID="CategoryIDTextBox" runat="server"
Text='<%# Bind("CategoryID") %>' />
</td>
<td>
<asp:TextBox ID="UnitPriceTextBox" runat="server"
Text='<%# Bind("UnitPrice") %>' />
</td>
</tr>
</InsertItemTemplate>
<LayoutTemplate>
<table runat="server">
<tr runat="server">
<td runat="server">
<table ID="itemPlaceholderContainer" runat="server" border="0" style="">
<tr runat="server" style="">
<th runat="server">
ProductID</th>
<th runat="server">
ProductName</th>
<th runat="server">
CategoryID</th>
<th runat="server">
UnitPrice</th>
</tr>
<tr ID="itemPlaceholder" runat="server">
</tr>
</table>
</td>
</tr>
<tr runat="server">
<td runat="server" style="">
</td>
</tr>
</table>
</LayoutTemplate>
<EditItemTemplate>
<tr style="">
<td>
<asp:Button ID="UpdateButton" runat="server" CommandName="Update" Text="更新" />
<asp:Button ID="CancelButton" runat="server" CommandName="Cancel" Text="取消" />
</td>
<td>
<asp:Label ID="ProductIDLabel1" runat="server"
Text='<%# Eval("ProductID") %>' />
</td>
<td>
<asp:TextBox ID="ProductNameTextBox" runat="server"
Text='<%# Bind("ProductName") %>' />
</td>
<td>
<asp:TextBox ID="CategoryIDTextBox" runat="server"
Text='<%# Bind("CategoryID") %>' />
</td>
<td>
<asp:TextBox ID="UnitPriceTextBox" runat="server"
Text='<%# Bind("UnitPrice") %>' />
</td>
</tr>
</EditItemTemplate>
<SelectedItemTemplate>
<tr style="">
<td>
<asp:Label ID="ProductIDLabel" runat="server" Text='<%# Eval("ProductID") %>' />
</td>
<td>
<asp:Label ID="ProductNameLabel" runat="server"
Text='<%# Eval("ProductName") %>' />
</td>
<td>
<asp:Label ID="CategoryIDLabel" runat="server"
Text='<%# Eval("CategoryID") %>' />
</td>
<td>
<asp:Label ID="UnitPriceLabel" runat="server" Text='<%# Eval("UnitPrice") %>' />
</td>
</tr>
</SelectedItemTemplate>
</asp:ListView>
<asp:SqlDataSource ID="SqlDataSource2" runat="server"
ConnectionString="<%$ ConnectionStrings:NorthwindConnectionString %>"
SelectCommand="SELECT [ProductID], [ProductName], [CategoryID], [UnitPrice] FROM [Products] WHERE ([CategoryID] = @CategoryID)">
<SelectParameters>
<asp:ControlParameter ControlID="drop" DefaultValue="1" Name="CategoryID"
PropertyName="SelectedValue" Type="Int32" />
</SelectParameters>
</asp:SqlDataSource>
</div>
</form>
</body>
</html>
/web.config
复制代码代码如下:
<connectionStrings>
<add name="NorthwindConnectionString" connectionString="Data
Source=.;Initial Catalog=Northwind;Integrated Security=True"
providerName="System.Data.SqlClient"/>
</connectionStrings>