Timer timer = new Timer(timerDelegate, s,1000, 1000);

timer.Change(1000,2000);

using System;
using System.Threading;
namespace ThreadExample
{
 class TimerExampleState 
 {
 public int counter = 0;
 public Timer tmr;
 }
 class App 
 {
 public static void Main()
 {
 TimerExampleState s = new TimerExampleState();
 //创建代理对象TimerCallback，该代理将被定时调用
 TimerCallback timerDelegate = new TimerCallback(CheckStatus);
  //创建一个时间间隔为1s的定时器
  Timer timer = new Timer(timerDelegate, s,1000, 1000);
  s.tmr = timer;
  //主线程停下来等待Timer对象的终止
  while(s.tmr != null)
  Thread.Sleep(0);
  Console.WriteLine("Timer example done.");
  Console.ReadLine();
 }
 //下面是被定时调用的方法
 static void CheckStatus(Object state)
 {
  TimerExampleState s =(TimerExampleState)state;
  s.counter++;
  Console.WriteLine("{0} Checking Status {1}.",DateTime.Now.TimeOfDay, s.counter);
  if(s.counter == 5)
  {
  //使用Change方法改变了时间间隔
  (s.tmr).Change(10000,2000);
  Console.WriteLine("changed");
  }
  if(s.counter == 10)
  {
  Console.WriteLine("disposing of timer");
  s.tmr.Dispose();
  s.tmr = null;
  }
 }
 }
}