Implementing a timeout in c#

Question

I am new to c#; I have mainly done Java.

I want to implement a timeout something along the lines:

int now= Time.now();
while(true)
{
  tryMethod();
  if(now > now+5000) throw new TimeoutException();
}

How can I implement this in C#? Thanks!

Answer 1

One possible way would be:

Stopwatch sw = new Stopwatch();
sw.Start();

while(true)
{
    tryMethod();
    if(sw.ElapsedMilliseconds > 5000) throw new TimeoutException();
}

However you currently have no way to break out of your loop. I would recommend having tryMethod return a bool and change it to:

Stopwatch sw = new Stopwatch();
sw.Start();

while(!tryMethod())
{
    if(sw.ElapsedMilliseconds > 5000) throw new TimeoutException();
}

Answer 2

I think you could do this with a timer and a delegate, my example code is below:

using System;
using System.Timers;

class Program
{
    public delegate void tm();

    static void Main(string[] args)
    {
        var t = new tm(tryMethod);
        var timer = new Timer();
        timer.Interval = 5000;

        timer.Start();

        timer.Elapsed += (sender, e) => timer_Elapsed(t);
        t.BeginInvoke(null, null);
    }

    static void timer_Elapsed(tm p)
    {
        p.EndInvoke(null);
        throw new TimeoutException();
    }

    static void tryMethod()
    {
        Console.WriteLine("FooBar");
    }
}

You have tryMethod, you then create a delegate and point this delegate at tryMethod, then you start this delegate Asynchronously. Then you have a timer, with the Interval being 5000ms, you pass your delegate into your timer elapsed method (which should work as a delegate is a reference type, not an value type) and once the 5000 seconds has elapsed, you call the EndInvoke method on your delegate.

Answer 3

The question is quite old, but yet another option.

using(CancellationTokenSource cts = new CancellationTokenSource(5000))
{
  cts.Token.Register(() => { throw new TimeoutException(); });
  while(!cts.IsCancellationRequested)
  {
    tryMethod();
  }
}

Technically, you should also propagate the CancellationToken in the tryMethod() to interupt it gracefully.

Working demo: (note I had to remove the exception throwing behavior as .netfiddle doesn't like it.)

https://dotnetfiddle.net/WjRxyk

Answer 4

As long as tryMethod() doesn't block this should do what you want:

Not safe for daylight savings time or changing time zones when mobile:

DateTime startTime = DateTime.Now;

while(true)
{
    tryMethod();
    if(DateTime.Now.Subtract(startTime).TotalMilliseconds > 5000)
        throw new TimeoutException();
}

Timezone and daylight savings time safe versions:

DateTime startTime = DateTime.UtcNow;

while(true)
{
    tryMethod();
    if(DateTime.UtcNow.Subtract(startTime).TotalMilliseconds > 5000)
        throw new TimeoutException();
} 

(.NET 3.5 or higher required for DateTimeOffset.)

DateTimeOffset startTime = DateTimeOffset.Now;

while(true)
{
    tryMethod();
    if(DateTimeOffset.Now.Subtract(startTime).TotalMilliseconds > 5000)
        throw new TimeoutException();
}