How to make a timer to do a long job?

Question

C++ / C#

There is a code.

// Создаем таймер из System.Threading
Timer timer = new Timer(OnTimer, state: null, dueTime: 0, period: 1000);

static void OnTimer(object state)
{
        Thread.Sleep(5000); // Симуляция работы
}

The problem is this.
Work goes 5 seconds. The timer interval is 1 second. As a result, in 1 second, 5 jobs will be launched simultaneously, which will be performed simultaneously. I would like the timer not to start a new one until the old one is completed.
I came up with this solution using System.Timers.Timer.

// Создаем таймер
timer = new System.Timers.Timer(1000);
timer.Elapsed += Timer_Elapsed;
timer.Start();

private static void Timer_Elapsed(object sender, System.Timers.ElapsedEventArgs e)
{
            timer.Stop(); // Останавливаем таймер чтобы он не вызвался второй раз через секунду.
            Thread.Sleep(5000); // Симуляция работы
            timer.Start();
}

As you can see, this solution is shit code for two reasons:
1. System.Timers.Timer is a Windows Forms component, and I'm writing a framework. It turns out ugly.
2. Before each return, you have to start a timer and also inside each catch.
Please advise the correct solution.

Answer 1

I use this solution, the timer waits until the work is finished. In fact, I just turn it off while the job is running, and after completion or exception, I start it again.

public class TestWorker
{
  private readonly Timer _timer;
  public TestWorker()   
  {
    _timer = new Timer(
      Callback, 
      null, 
      TimeSpan.FromSeconds(1),          
      TimeSpan.Zero);
  }

  private void Callback(object state)
  {
    try
    {
      //work imitation
      Thread.Sleep(5000);
    }
    finally
    {
      _timer.Change(
        TimeSpan.FromSeconds(1),    
        TimeSpan.Zero);
    }
  }
}

Answer 2

This is how you separate the timer and payload. And in the timer you check if the old one is still working, then you don’t start the new one.