C# Threading/Async: Running a task in the background while UI is interactable

After looking around on both Async/Await and Threading, I'm still unsure of the right way to apply it to my situation. No matter the variation that I try my UI still hangs because I don't seem to be calling my desired function asynchronously, additionally, I may in fact need threading for my solution.

What I'm trying to do: I have a WPF application on which there is a button that I would like to start an operation that still allows interaction with the program, through UI or otherwise. Once a condition is met that is determined outside of this function, the function should end. To me this sounds fairly standard but I have a feeling I'm misunderstanding something and I've implemented it incorrectly.

What I have right now: 

private async void start_button_Click(object sender, RoutedEventArgs e)
{
    await StaticClass.MyFunction();
}

private void stop_button_Click(object sender, RoutedEventArgs e)
{
    StaticClass.stopFlag = true;
}

public static Task<int> myFunction()
{
    //Stuff Happens

    while(StaticClass.stopFlag == false)
        //Do Stuff

    //Stuff Happens

    return Task.FromResult(1) //I know this is bad, part of the reason I'm asking
}

I was hoping for some guidance on if I'm approaching this the right way and any insight on what I'm doing wrong.

Jon Skeet
people
quotationmark

You've definitely implemented it incorrectly. You're returning a Task<int>, but only once all the work has already been done.

It seems to me that you should probably just have a synchronous method:

private static void MyFunction()
{
    // Loop in here
}

Then start a task for it like this:

Task task = Task.Run((Action) MyFunction);

You can then await that task if you want - although in the example you've given, there's no point in doing so, as you're not doing anything after the await anyway.

I'd also agree with Reed that using a CancellationToken would be cleaner than a static flag somewhere else.

people

See more on this question at Stackoverflow