AsyncLock.IsTaken needed about asyncex HOT 8 CLOSED

The first thing that comes to mind with notification is that you'd naturally have cross-thread issues (why else have a lock?).
I can see merit in the idea but there'd have to be warnings for people to not rely on it as a "this lock is available" because race conditions, yada yada :)

Nothing that can't be solved with a bit of documentation I suppose :)

from asyncex.

I agree with your comment about the race condition. However I don't see any other way to notify a button that it needs to disable itself when the critical section has been entered.. If there is some other way to do it then please let me know. I do think we need to be able to notify the UI that a critical section is active / locked.

I also agree with the cross-thread comment, although I would say this is kind of a "normal" problem.

from asyncex.

The IsTaken is being considered as part of the new API. It won't ever notify, though; updating the UI is a completely disparate operation than serialization of access.

@sjb-sjb Enabling/disabling a control based on something outside the user's control seems like very odd UX to me. The user could easily click on a button, see it become disabled, and yet not have any response to their action. If you could describe your use case in more detail, maybe I can suggest an alternative approach?

from asyncex.

Well, I am copying my sqlite database to and from the appdir so that the user can see their file in their documents directory. I have file open and file new commands that copy an existing or new file respectively. I want to disable file new while file open is in the critical section (which is pretty much all of file open) and vice versa.

Thanks for your comments.

from asyncex.

In that case, I'd just disable the New button while the Open command is in progress.

from asyncex.

Well, yes, I agree. It's just a question of whether "in progress" is coming from the ViewModel or from the Model / service. I just thought the service (file service in this case) should be able to tell all users whether or not an operation is in progress / the service is busy.

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On May 30, 2016, at 10:15 AM, Stephen Cleary [email protected] wrote:

In that case, I'd just disable the New button while the Open command is in progress.

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from asyncex.

If your Model uses INotifyPropertyChanged, then there's no reason not to expose AsyncCommands / NotifyTask from your Model. Personally, I usually don't write my models like that, but if you do, they should work just fine.

from asyncex.

There appear to be more appropriate alternative solutions for this use case rather than exposing IsTaken.

from asyncex.