How not to let application exit when tasks are running

Question

Is there any framework support for the cases when application is going to close but there are some not completed tasks?

Tasks run in the context of background thread by default. Sometimes it's ok just to let the task complete:

Task.Factory.StartNew(() =>
                          {
                              Thread.CurrentThread.IsBackground = false;
                              Thread.Sleep(20000);
                              Thread.CurrentThread.IsBackground = true;
                          });

But this doesn't work if task has continuations which require completition. Especially if some of the tasks will run under UI thread.
It is possible to get all the "final" tasks and to postpone the application exit with WhenAll().
Yet I do not know how to do the same when async/await is used.

So I'd like to know if there's any support for such cases. Are there any guarantees which framework gives or ways to enforce them?

The only way I see now is setting flags as a sign that critical tasks are not completed yet.

Stephen Cleary Stephen Cleary · Accepted Answer · 2013-03-27T11:58:37

As an aside, you should not set IsBackground on a thread pool thread.

For async methods, ensure your methods are returning Task and not void, and then you can await them all using WhenAll. You can have your event handlers capture the top-level Tasks rather than await them.

How not to let application exit when tasks are running

1 Answers