Question

I have a c# console application which has some threads to do some work (download a file).
each thread may exit the application at any time any where in application, but I’ll show a proper message on console. It’s possible to track them but it doesn’t make sense to me. I want simply check thread count or something like that to find out which one is the last thread and do something when it is exiting.
What’s the best practice to do so ?

pseudo code:

if (lastThread)
{
   cleanUp();
   Console.ReadLine();
}

Thanks

Answer 1

This is one place where using the new Task Parallel Library can make life much easier. Instead of creating threads, and spinning work up on the thread, you can use multiple tasks:

var task1 = Task.Factory.StartNew( () => DoTaskOneWork() );
var task2 = Task.Factory.StartNew( () => DoTaskTwoWork() );
var task3 = Task.Factory.StartNew( () => DoTaskThreeWork() );

// Block until all tasks are done

Task.WaitAll(new[] {task1, task2, task3} );
cleanUp(); // Do your cleanup

If the “tasks” are just downloading a bunch of individual files, you could even make this simpler using PLINQ:

var fileUrls = GetListOfUrlsToDownload();

fileUrls.AsParallel().ForAll( fileUrl => DownloadAndProcessFile(fileUrl) );

cleanUp(); // Do your cleanup