Here's what I came up with.
SmartDispatcherTimer
Extends DispatcherTimer
(was easiest way to get this up and running)
- Has a
TickTask
property to provide a Task
to handle the logic
- Has an
IsReentrant
property (of course the whole point is that I want it to not be reentrant so normally this is false)
- It assumes anything you're calling is fully awaitable - or you'd end up losing the reentrancy protection benefits
Usage:
var timer = new SmartDispatcherTimer();
timer.IsReentrant = false;
timer.Interval = TimeSpan.FromSeconds(30);
timer.TickTask = async () =>
{
StatusMessage = "Updating..."; // MVVM property
await UpdateSystemStatus(false);
StatusMessage = "Updated at " + DateTime.Now;
};
timer.Start();
Here's the code. Would love to hear any thoughts on it
public class SmartDispatcherTimer : DispatcherTimer
{
public SmartDispatcherTimer()
{
base.Tick += SmartDispatcherTimer_Tick;
}
async void SmartDispatcherTimer_Tick(object sender, EventArgs e)
{
if (TickTask == null)
{
Debug.WriteLine("No task set!");
return;
}
if (IsRunning && !IsReentrant)
{
// previous task hasn't completed
Debug.WriteLine("Task already running");
return;
}
try
{
// we're running it now
IsRunning = true;
Debug.WriteLine("Running Task");
await TickTask.Invoke();
Debug.WriteLine("Task Completed");
}
catch (Exception)
{
Debug.WriteLine("Task Failed");
}
finally
{
// allow it to run again
IsRunning = false;
}
}
public bool IsReentrant { get; set; }
public bool IsRunning { get; private set; }
public Func<Task> TickTask { get; set; }
}
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