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源视图代码：
1 <%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %>
2
3 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
4 <html xmlns="http://www.w3.org/1999/xhtml">
5 <head id="Head1" runat="server">
6 <title>Timer Example Page</title>
7 <link href="DivStyles.css" rel="stylesheet" type="text/css" />
8 </head>
9 <body>
10 <form id="form1" runat="server">
11 <asp:ScriptManager ID="ScriptManager1" runat="server" />
12 <asp:Timer ID="Timer1" OnTick="Timer1_Tick" runat="server" Interval="1000" />
13 <br />
14 <hr />
15 <br />
16 Some content ..............<br />
17 <br />
18 <asp:UpdatePanel ID="BannerPanel" runat="server" UpdateMode="Conditional">
19 <Triggers>
20 <asp:AsyncPostBackTrigger ControlID="Timer1" />
21 </Triggers>
22 <ContentTemplate>
23 <asp:Image ID="BannerImage" runat="server" ImageUrl="~/banners/banner_1.gif" />
24 </ContentTemplate>
25 </asp:UpdatePanel>
26 <br />
27 <div>
28 Some more content ..........<br />
29 <br />
30 </div>
31 </form>
32 </body>
33 </html>
1 protected void Timer1_Tick(object sender, EventArgs e)
2 {
3 Random RandomClass = new Random();
4 int n = RandomClass.Next(1, 9);
5 BannerImage.ImageUrl = System.String.Concat("banners/Banner_", n.ToString(), ".gif");
6 }
代码的作用是产生1-9的任意随机数，来选择不同的图片的呈现。