Sleep inside for loop in wpf

问题

I have been working with WPF and threading.

I would like to pause the whole screen (the application only) during a for loop.

E.g.

foreach (classA a in classesA)
{
....
....
Thread.sleep(100);

}

However, I found that it will sleep for long and then execute all the statement in a time. It is not what I want. I want to sleep within the execution of the for loop. That is to sleep 100ms after 1st loop, then sleep again after the 2nd loop.....

I found that some article mentioned DoEvents(), but I am not quite familiar with it and WPF seem don't have this kind of thing.

Some other articles mentioned DispatcherTimer. Still, it will not lock the screen. I would like to lock the whole screen (the application only) to prevent from clicking any button during the execution of the for loop.

How could I do so?

Thank you so much!

回答1:

If you are willing to experiment to with the proposed async and await keywords you could achieve the sleep behavior with synchronous semantics like this. You would need to install the Async CTP to do it though.¹

public aysnc void YourButton_Click(object sender, EventArgs args)
{
  foreach (classA a in classes)
  {
    await Task.Delay(100);
  }
}

---

¹The Async CTP uses TaskEx instead of Task.

回答2:

You must not block the UI-thread otherwise it cannot process its queue, which contains rendering the UI, if you want to block interaction with UI-elements set IsEnabled=false on a root element, then to do a non-blocking wait see this question.

来源：https://stackoverflow.com/questions/8078596/sleep-inside-for-loop-in-wpf