Timers in .NET

I was researching timers the other day and realized that there are three variations in the .NET Framework.

The three types of timers are explained below.

1 – System.Timers.Timer

The System.Timers.Timer class timer is considered a server-based timer that was designed and optimized for use in multithreaded environments. It can be accessed safely from multiple threads.

C# Program

using System;
using System.Timers;

public class Program
{
  private static System.Timers.Timer testTimer;

  public static void Main(string[] args)
  {
    testTimer = new System.Timers.Timer(5000); // 5 seconds
    testTimer.Elapsed += new ElapsedEventHandler(OnTimerElapsed);

    testTimer.Interval = 5000;
    testTimer.Enabled = true;

    Console.WriteLine("Press the enter key to stop the timer");
    Console.ReadLine();

  }

  private static void OnTimerElapsed(object source, ElapsedEventArgs e)
  {
    Console.WriteLine("Timer elapsed at {0}", e.SignalTime);
  }
}

C# Listing on GitHub 

Output

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2 – System.Threading.Timer

The System.Threading.Timer class timer uses a TimerCallBack Delegate to specify the associated methods. The methods do not execute in the thread that created the timer; they execute in a separate thread that is automatically allocated by the system.

C# Program

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();
     }
  }
}

Output

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3 – Windows.Forms.Timer

The Windows.Forms.Timer class works synchronously with the Windows Form, so that it will not interrupt any operations. It initializes on the UI thread.

C# Program

using System;
using System.Windows.Forms;

namespace WindowsFormsTimer
{
  public class Class1
  {
     static System.Windows.Forms.Timer theTimer = 
         new System.Windows.Forms.Timer();

     static int alarmCounter = 1;
     static bool exitFlag = false;

      // Timer raised method
      private static void TimerEventProcessor(Object myObject, 
          EventArgs myEventArgs)
      {
         theTimer.Stop();

         // Displays a message box asking whether to continue to run the timer
         if (MessageBox.Show("Continue running?", "Count is " + 
             alarmCounter, MessageBoxButtons.YesNo) == DialogResult.Yes)
         {
             // Restarts the timer and increments the counter
             alarmCounter += 1;
             theTimer.Enabled = true;
         }
         else
         {
             // Stops the timer
             exitFlag = true;
         }
     }

     public static int Main()
     {
         //Adds the event and the event handler for the method that will 
         //process the timer event to the timer
         theTimer.Tick += new EventHandler(TimerEventProcessor);

         // Sets the timer interval to 5 seconds
         theTimer.Interval = 2000;
         theTimer.Start();

         // Runs the timer, and raises the event
         while (exitFlag == false)
         {
             // Processes all the events in the queue
             Application.DoEvents();
         }
         return 0;
     }
  }
}

C# Listing on GitHub  

Output

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There are three choices for timers in .NET.  It just depends on what you want to do.

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More Information

• Comparing the Timer Classes in the .NET Framework Class Library
• System.Timers.Timer vs System.Threading.Timer
• Working with Timer Control in VB.NET

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Until next time…

^..^