大约每分钟运行一次任务而不使用Thread.Sleep

Question

I have a method in C# that I would run, then wait a minute before restarting the method again.

Right now, I am just using

while(true)
{
    this.DoMyMethod();

    Thread.Sleep(TimeSpan.FromMinutes(1));
}

While this works, I am wondering if there is a more elegant way of doing this? The issue with Timers, is they'll run even if the last timer fire call hasn't finished yet.

Answer 1

So make an asynchronous loop:

public async Task DoMyThing(CancellationToken token = default(CancellationToken))
{
     while(!token.IsCancellationRequested)
     {
         this.DoMyMethod();
         try
         {
             await Task.Delay(TimeSpan.FromMinutes(1), token);
         }
         catch(TaskCanceledException)
         {
             break;
         }
     }
}

This code is guaranteed not to overlap the invocations of DoMyMethod , so the delay (much in the same way as Thread.Sleep ) happens between invocations.

If you create a CancellationTokenSource , you can pass its Token to your method and you can kill the loop by calling Cancel on the CancellationTokenSource .

Note: CancellationToken.None === default(CancellationToken)

Answer 2

With System.Timers.Timer you can set AutoReset to false meaning the timer will only run once, you'd have to call Start() again to restart it.

So in your timer tick method simply call Start() after you've done what you need to and you're ready to begin again.

For example:

public SomeClass()
{
    Timer timer = new Timer(60000);
    timer.Elapsed += new ElapsedEventHandler(OnElapsed);
    timer.AutoReset = false;
    timer.Start();
}

private void OnElapsed(object sender, ElapsedEventArgs e)
{
    // Do stuff

    timer.Start(); // Restart timer
}

Answer 3

A timer is still your option. If you are concerned about it tripping again before the first timer firing process has completed, the stop the timer while the process runs, and then restart it when your process completes.