请帮我看看这是咋回事啊，我的程序运行不到OnTimedEvent(),运行结果是：是什么啊3。

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.Timers;
using System.Windows.Forms;

public partial class _Default : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
       
    }
    protected void Button1_Click(object sender, EventArgs e)
    {
        System.Timers.Timer aTimer = new System.Timers.Timer();
        Button1.Text = "是什么啊1";
        aTimer.Elapsed += new ElapsedEventHandler(OnTimedEvent);
        aTimer.Interval = 2000;
        Button1.Text = "是什么啊2";
        aTimer.Enabled = true;
        Button1.Text = "是什么啊3";
    }
    protected void OnTimedEvent(object source, ElapsedEventArgs e)
    {
        Button1.Text = "是什么4啊";
    }
}