using System;
using System.Threading;
 
class Program
{
    static void Main()
    {
        AutoResetEvent reset = new AutoResetEvent(false);
        StatusChecker status = new StatusChecker(5);
 
        // Invoke methods for the timer via a Delegate
        TimerCallback timerDelegate = new TimerCallback(status.CheckStatus);
 
        // Create a timer that signals the delegate to invoke 
        // Check status after one second, and then every 1/4 second
        Console.WriteLine("{0} Creating the timer.\n",DateTime.Now.ToString("h:mm:ss.fff"));
        Timer stateTimer = new Timer(timerDelegate, reset, 1000, 250);
 
        // When the auto reset executes, change to every 1/2 second
        reset.WaitOne(5000, false);
        stateTimer.Change(0, 500);
        Console.WriteLine("\nChanging the timer period.\n");
 
        reset.WaitOne(5000, false);
        stateTimer.Dispose();
        Console.WriteLine("\nDestroying the timer.");
    }
}
 
class StatusChecker
{
    int invokeCount, maxCount;
 
    public StatusChecker(int count)
    {
        invokeCount = 0;
        maxCount = count;
    }
 
    // This method is called by the timer delegate.
    public void CheckStatus(Object stateInfo)
    {
        AutoResetEvent autoEvent = (AutoResetEvent)stateInfo;
        Console.WriteLine("{0} Checking status {1,2}.",
            DateTime.Now.ToString("h:mm:ss.fff"),
            (++invokeCount).ToString());
 
        if (invokeCount == maxCount)
        {
            // Reset the counter and signal Main.
            invokeCount = 0;
            autoEvent.Set();
        }
    }
}