.Net core 6 - About Async Task run in constructor, the VSCode Debugger is not work

I have a Task that needs to continuously poll devices for information, so I created the Task in the constructor.

public DeviceManager()
{
    Task.Run(Polling);
}

private Func<Task> Polling()
{
    return async () =>
        {
            while (true)
            {
                await GetInfo();
                await Task.Delay(60 * 1000);
            }
        }
}

I usually run dotnet watch --no-hot-reload to test my program, but now I want to debug it.

However, when the debugger is running, it hangs in this while loop.

Please let me know why I cannot debug in this situation.

Thanks.

The task is never stored anywhere so it's probably garbage-collected before it ever has a chance to get scheduled for execution. In fact, unless DeviceManager is a Singleton, the class itself may get garbage-collected as soon as the request that spawned it completes. A Task isn't a thread, it represents some work that needs to complete in the future. If the task itself gets orphaned before it gets scheduled, the work is lost.

Creating background services in ASP.NET Core is done by implementing the IHostedService interface. This is described in Background tasks with hosted services in ASP.NET Core. That article shows both a poll service and a queued job service example.

The timed background service is pretty simple and uses a timer to call its DoWork method periodically:

public class TimedHostedService : IHostedService, IDisposable
{
    private int executionCount = 0;
    private readonly ILogger<TimedHostedService> _logger;
    private Timer? _timer = null;

    public TimedHostedService(ILogger<TimedHostedService> logger)
    {
        _logger = logger;
    }

    private void DoWork(object? state)
    {
        var count = Interlocked.Increment(ref executionCount);

        _logger.LogInformation(
            "Timed Hosted Service is working. Count: {Count}", count);
    }

    public Task StartAsync(CancellationToken stoppingToken)
    {
        _logger.LogInformation("Timed Hosted Service running.");

        _timer = new Timer(DoWork, null, TimeSpan.Zero,
            TimeSpan.FromSeconds(5));

        return Task.CompletedTask;
    }

    public Task StopAsync(CancellationToken stoppingToken)
    {
        _logger.LogInformation("Timed Hosted Service is stopping.");

        _timer?.Change(Timeout.Infinite, 0);

        return Task.CompletedTask;
    }

    public void Dispose()
    {
        _timer?.Dispose();
    }
}

The StartAsync and StopAsync are called by the ASP.NET Core host to start and stop the service. In this case all they have to do is start and stop the timer.