利用AJAX实现DropDownList与GridView做实时更新
本实例是完全用页面设置的方法，就可以达到的效果，不用编写任何后台代码，方便实用。需要先建立一个ASP.NET AJAX-Enabled Web Site，然后建立一个资料库，就可以使用了。
*.aspx:
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="ddlGridview_CS.aspx.cs" Inherits="ddlGridview_CS" %>
<!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>Test</title>
</head>
<body>
<form id="form1" runat="server">
<div>
<asp:ScriptManager ID="ScriptManager1" runat="server">
</asp:ScriptManager>
<asp:DropDownList ID="DropDownList1" runat="server" AutoPostBack="True">
<asp:ListItem Selected="True" Value="False">Active</asp:ListItem>
<asp:ListItem Value="True">Complete</asp:ListItem>
</asp:DropDownList>
<asp:UpdatePanel ID="UpdatePanel1" runat="server">
<ContentTemplate>
<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False" DataKeyNames="TaskID"
DataSourceID="SqlDataSource1" CellPadding="4" ForeColor="#333333" GridLines="None">
<Columns>
<asp:BoundField DataField="TaskID" HeaderText="TaskID" InsertVisible="False" ReadOnly="True"
SortExpression="TaskID" />
<asp:BoundField DataField="TaskName" HeaderText="TaskName" SortExpression="TaskName" />
<asp:CheckBoxField DataField="Complete" HeaderText="Complete" SortExpression="Complete" />
</Columns>
<FooterStyle BackColor="#5D7B9D" Font-Bold="True" ForeColor="White" />
<RowStyle BackColor="#F7F6F3" ForeColor="#333333" />
<EditRowStyle BackColor="#999999" />
<SelectedRowStyle BackColor="#E2DED6" Font-Bold="True" ForeColor="#333333" />
<PagerStyle BackColor="#284775" ForeColor="White" HorizontalAlign="Center" />
<HeaderStyle BackColor="#5D7B9D" Font-Bold="True" ForeColor="White" />
<AlternatingRowStyle BackColor="White" ForeColor="#284775" />
</asp:GridView>
</ContentTemplate>
<Triggers>
<asp:AsyncPostBackTrigger ControlID="DropDownList1" EventName="SelectedIndexChanged" />
</Triggers>
</asp:UpdatePanel>
<asp:SqlDataSource ID="SqlDataSource1" runat="server" ConnectionString="<%$ ConnectionStrings:DatabaseConnectionString %>"
SelectCommand="SELECT * FROM [Tasks] where Complete = @IsComplete">
<SelectParameters>
<asp:ControlParameter ControlID="DropDownList1" Name="IsComplete" PropertyName="SelectedValue" />
</SelectParameters>
</asp:SqlDataSource>
</div>
</form>
</body>
</html>
