Systems.Timers.Timer works in debug, but not release

Question

System.Timers.Timer timer= new System.Timers.Timer(1);
            timer.AutoReset = true;
            timer.Elapsed += (s, e) =>
            {
                Console.WriteLine("fired");
            };
timer.Start();

The event is consistently fired in debug mode, and consistently not fired in release mode. I tried disabling compiler optimizations, but it didn't help.

I am trying to run this in an asp.net mvc application .net 4.6 framework

Answer 1

Your timer is probably fine, but your method of testing that is flawed.

Data written to Console.WriteLine in release mode in ASP.NET applications is lost. See the answer to this question: Where does Console.WriteLine go in ASP.net production environment?

If you really want to use Console.WriteLine, you can use Console.SetOut to redirect the output to a file.

Also, make sure your timer object is not declared inside a method since it will be destroyed as soon as the method completes.

Answer 2

Your timer is set to 1ms. That could produce some unpredictable results because the "resolution" - the intervals at which the timer is checked - is typically around 15ms. If you're just trying to test the behavior of a timer then I'd increase it to maybe 20ms or more.

I tested this. A 1ms interval running for 500ms consistently elapsed 32 times - roughly once every 15ms. This was the same in debug and release. No exceptions were thrown.

Instead of writing to the console I'd recommend adding items to a globally accessible ConcurrentQueue when the timer elapses (since this is just for testing/experimentation.)

Then on a web page you could output the contents of the queue. You might want to stop the timer first so it doesn't keep pumping items into the queue. (Or just use a longer interval.)

Answer 3

Hope the following solution helps!

Problem:

The following code always works as expected by showing the current clock time.

 class Program
 {
        static void TimerProcedure(object param)
        {
            Console.Clear();
            Console.WriteLine(DateTime.Now.TimeOfDay);

            GC.Collect();

        }

        static void Main(string[] args)
        {
            Console.Title = "Desktop Clock";
            Console.SetWindowSize(20, 2);
            Timer timer = new Timer(TimerProcedure, null,
                TimeSpan.Zero, TimeSpan.FromSeconds(1));
            Console.ReadLine();
        }
    }

However, if you run the same code in release mode, it shows current time only for the first time but it never updates after that.

Solution

A simple tweak by adding GC.KeepAlive(object) will make it work in Release mode also as expected. Refer to code below.

class Program
    {
        static void TimerProcedure(object param)
        {
            Console.Clear();
            Console.WriteLine(DateTime.Now.TimeOfDay);
            #region Hidden
            GC.Collect();
            #endregion
        }

        static void Main(string[] args)
        {
            Console.Title = "Desktop Clock";
            Console.SetWindowSize(20, 2);
            Timer timer = new Timer(TimerProcedure, null,
                TimeSpan.Zero, TimeSpan.FromSeconds(1));
            Console.ReadLine();
            GC.KeepAlive(timer);
        }
    }

Coming to your specific problem, verify if the scope of timer variable is local to a method. If that is true, you can keep it alive as shown above.

Alternate solution: is making timer a class level static variable