页面代码：
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %>
<%@ Register Assembly="AjaxControlToolkit" Namespace="AjaxControlToolkit" TagPrefix="cc1" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head id="Head1" runat="server">
<title>Untitled Page</title>
<style type="text/css">
#UpdatePanel3 {
border-right: gray 1px solid; border-top: gray 1px solid;
border-left: gray 1px solid; border-bottom: gray 1px solid;
width:200px; height:200px; position: relative;
float: left; margin-left: 10px; margin-top: 10px;
}
</style>
</head>
<body>
<form id="form1" runat="server">
<asp:ScriptManager ID="ScriptManager1" runat="server" />
<asp:UpdatePanel ID="UpdatePanel3" runat="server">
<ContentTemplate>
<asp:Timer ID="Timer1" runat="server" Interval="1000" OnTick="Timer1_Tick">
</asp:Timer>
<asp:Label ID="Label3" runat="server" Text="Label"></asp:Label><br />
</ContentTemplate>
</asp:UpdatePanel>
<asp:Label ID="Label4" runat="server" Text="Label"></asp:Label>
</form>
</body>
</html>
cs文件代码：
using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Threading;
public partial class _Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
Label4.Text = "初始化时间：" + DateTime.Now.ToString();
Timer1.Interval = 1000;
}
protected void Timer1_Tick(object sender, EventArgs e)
{
Label3.Text = "刷新时间：" + DateTime.Now.ToString();
}
}