Replace IGuardClose.CanClose with CanCloseAsync

The current syntax of CanClose with a callback is quite difficult to chain. For example, if I’m deriving from a class already overriding CanClose and want to first check that it allowed closing before adding my own condition, the code will look like this:

public override void CanClose(Action<bool> callback) {
  base.CanClose(result => callback(result && condition));
}

By making CanCloseAsync, it’s way more natural IMO:

public override Task<bool> CanCloseAsync() {
  return await base.CanCloseAsync() && condition();
}

Plus, it allows to call other asynchronous methods easily. Of course, that would be a breaking change, unless a new interface is implemented.

[enrico-padovani]

Hi folks!

Any progress on this / ETA for v4? In my specific case I’m using MahApps message which is implemented in async way. So when trying to close a screen, I’d like to ask for modification discard. Perhaps someone has solved this problem.

[nigel-sampson]

Would be good to have a second interface for this, otherwise we’re back to breaking changes and needing to release 3.0.0