CODEWITHSUNDEEP
c#waitfreeze
Ahmad
Ahmad

Reputation: 9658

How to wait for a function execution for specific duration

My C# application stops responding for a long time, as I break the Debug it stops on a function.

foreach (var item in list)
{
    xmldiff.Compare(item, secondary, output);
    ...
}

I guess the running time of this function is long or it hangs. Anyway, I want to wait for a certain time (e.g. 5 seconds) for the execution of this function, and if it exceeds this time, I skip it and go to the next item in the loop. How can I do it? I found some similar question but they are mostly for processes or asynchronous methods.

Upvotes: 1

Views: 951

Answers (3)

Cheng Chen
Cheng Chen

Reputation: 43523

I skip it and go to the next item in the loop

By "skip it", do you mean "leave it there" or "cancel it"? The two scenarios are quite different. But for both two I suggest you use Task.

//generate 10 example tasks
var tasks = Enumerable
    .Range(0, 10)
    .Select(n => new Task(() => DoSomething(n)))
    .ToList();

var maxExecutionTime = TimeSpan.FromSeconds(5);

foreach (var task in tasks)
{
    if (task.Wait(maxExecutionTime))
    {
        //the task is finished in time
    }
    else
    {
        // the task is over time
        // just leave it there
        // the loop continues
        // if you want to cancel it, see 
        // http://stackoverflow.com/questions/4783865/how-do-i-abort-cancel-tpl-tasks
    }
}

One thing to improve is "do you really need to run your tasks one by one?" If they are independent you can run them in parallel.

Upvotes: 0

Enigmativity
Enigmativity

Reputation: 117064

I would avoid directly using threads and use Microsoft's Reactive Extensions (NuGet "Rx-Main") to abstract away the management of the threads.

I don't know the exact signature of xmldiff.Compare(item, secondary, output) but if I assume it produces an integer then I could do this with Rx:

var query =
    from item in list.ToObservable()
    from result in
        Observable
            .Start(() => xmldiff.Compare(item, secondary, output))
            .Timeout(TimeSpan.FromSeconds(5.0), Observable.Return(-1))
    select new { item, result };

var subscription =
    query
        .Subscribe(x =>
        {
            /* do something with `x.item` and/or `x.result` */
        });

This automatically iterates through each item and starts a background computation of xmldiff.Compare, but only allows each computation to take as much as 5.0 seconds before returning a default value of -1.

The subscription variable is an IDisposable, so if you want to abort the entire query before it completes just call .Dispose().

Upvotes: 0

Haukinger
Haukinger

Reputation: 10863

You can do it the brutal way: spin up a thread to do the work, join it with timeout, then abort it, if the join didn't work.

Example:

var worker = new Thread( () => { xmlDiff.Compare(item, secondary, output); } );
worker.Start();
if (!worker.Join( TimeSpan.FromSeconds( 1 ) ))
    worker.Abort();

But be warned - aborting threads is not considered nice and can make your app unstable. If at all possible try to modify Compare to accept a CancellationToken to cancel the comparison.

Upvotes: 3

Related Questions