İlkay İlknur

A New Modern Timer API In .NET 6 - PeriodicTimer

October 11, 2021

As a developer, you've probably used timers in .NET before. There are plenty of types of timers in .NET right now, and each of them serves a different purpose.

List of types of timers in .NET 5.

  • System.Threading.Timer
  • System.Timers.Timer
  • System.Windows.Forms.Timer
  • System.Web.UI.Timer
  • System.Windows.Threading.DispatcherTimer

.NET 6 introduces a new timer type called PeriodicTimer. The main purpose behind the PeriodicTimer is to avoid using callbacks. Avoiding callbacks can save us from dealing with memory leaks that might occur in long-lived operations, and we can write async code instead of using the sync over async approach in callbacks. Another problem that you might deal with with the current timer types is callback overlapping. If you don't write code for the callback overlap scenario, you can see unexpected behaviors in your application.

Creating a PeriodicTimer instance is pretty straightforward. The only parameter you need to provide is the period value.

var timer = new PeriodicTimer(TimeSpan.FromSeconds(10));

You can call the WaitForNextTickAsync method to wait asynchronously between ticks and, write asynchronous code without dealing with callback overlapping problems because the PeriodicTimer pauses while the business code is running and resumes when the WaitForNextTickAsync method is called.

var timer = new PeriodicTimer(TimeSpan.FromSeconds(10));

while (await timer.WaitForNextTickAsync())
    //Business logic

You can stop PeriodicTimer using the CancellationToken that you can specify while calling the WaitForNextTickAsync method. Another way to stop the PeriodicTimer is calling the Dispose method. When the Dispose method is called, WaitForNextTickAsync returns false, and you can stop executing the timer-based business logic.

Some notes about PeriodicTimer

  • The execution context isn't captured.
  • PeriodicTimer is intended to be used only by a single consumer at a time.

PeriodicTimer documentation: