C# - TimerCallback Delegate

TimerCallback Delegate

Represents the method that handles calls from a Timer.

using System;

using System.Threading;

class TimerExample

{

    static void Main()

    {

        // Create an AutoResetEvent to

        // signal the timeout threshold in the

        // timer callback has been reached.

        var autoEvent = new AutoResetEvent(false);

       

        var statusChecker = new StatusChecker(10);

        // Create a timer that invokes CheckStatus after one second,

        // and every 1/4 second thereafter.

        Console.WriteLine("{0:h:mm:ss.fff} Creating timer.\n",

                          DateTime.Now);

        var stateTimer = new Timer(statusChecker.CheckStatus,

                                   autoEvent, 1000, 250);

        // When autoEvent signals, change the period to every half second.

        autoEvent.WaitOne();

        stateTimer.Change(0, 500);

        Console.WriteLine("\nChanging period to .5 seconds.\n");

        // When autoEvent signals the second time, dispose of the timer.

        autoEvent.WaitOne();

        stateTimer.Dispose();

        Console.WriteLine("\nDestroying timer.");

    }

}

class StatusChecker

{

    private int invokeCount;

    private int  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 the waiting thread.

            invokeCount = 0;

            autoEvent.Set();

        }

    }

}

// The example displays output like the following:

//       11:59:54.202 Creating timer.

//      

//       11:59:55.217 Checking status  1.

//       11:59:55.466 Checking status  2.

//       11:59:55.716 Checking status  3.

//       11:59:55.968 Checking status  4.

//       11:59:56.218 Checking status  5.

//       11:59:56.470 Checking status  6.

//       11:59:56.722 Checking status  7.

//       11:59:56.972 Checking status  8.

//       11:59:57.223 Checking status  9.

//       11:59:57.473 Checking status 10.

//      

//       Changing period to .5 seconds.

//      

//       11:59:57.474 Checking status  1.

//       11:59:57.976 Checking status  2.

//       11:59:58.476 Checking status  3.

//       11:59:58.977 Checking status  4.

//       11:59:59.477 Checking status  5.

//       11:59:59.977 Checking status  6.

//       12:00:00.478 Checking status  7.

//       12:00:00.980 Checking status  8.

//       12:00:01.481 Checking status  9.

//       12:00:01.981 Checking status 10.

//      

//       Destroying timer.