Running long tasks without freezing the UI

Question

I am trying to perform an action in the background, without freezing the UI.

Of course, I could use BackgroundWorker for this.

However, I'd like to do it with the Task API only.

I tried:

async void OnTestLoaded(object sender, RoutedEventArgs e)
{
   await LongOperation();
}
// It freezes the UI

and

async void OnTestLoaded(object sender, RoutedEventArgs e)
{
   var task = Task.Run(()=> LongOperation());
   task.Wait();
}


// It freezes the UI

So should I go back to BackgroundWorker? Or is there a solution using Tasks only?

Answer 1

You were pretty close.

async void OnTestLoaded(object sender, RoutedEventArgs e)
{
  await Task.Run(() => LongOperation());
}

async does not execute a method on a thread pool thread.

Task.Run executes an operation on a thread pool thread and returns a Task representing that operation.

If you use Task.Wait in an async method, you're doing it wrong. You should await tasks in async methods, never block on them.