[BUG] PopupService.ShowPopup causes Behavior.OnAttached to execute more than once

[bengavin]

Is there an existing issue for this?

• I have searched the existing issues

Did you read the "Reporting a bug" section on Contributing file?

• I have read the "Reporting a bug" section on Contributing file: https://github.com/CommunityToolkit/Maui/blob/main/CONTRIBUTING.md#reporting-a-bug

Current Behavior

When a behavior is added to the view's Behaviors collection, and the PopupService ShowPopup [or ShowPopupAsync] method is called, the behavior is re-attached even though it was already in the behaviors collection.

Expected Behavior

The behavior is only attached once, even if ShowPopup is called.

Steps To Reproduce

1. Open the Issue.PlatformBehaviorPopupService solution and run the application
2. Notice the Debug 'Output' window and see the 'attached' events
3. Click the 'Click me!' button
4. Monitor the Debug 'Output' window and notice that a new 'attached' event logged each time the button is clicked

Link to public reproduction project repository

https://github.com/bengavin/maui-issue-repros/tree/main/Issue.PlatformBehaviorPopupService

Environment

- .NET MAUI CommunityToolkit: 9
- OS: Windows
- .NET MAUI: 8.0.40

Anything else?

No response

[bijington]

Just to double check do you see any detached events logged?

Also you don't want to be registering your PopupViewModel as a singleton and a transient. I'd remove the Singleton registration from your MauiProgram file.

[bengavin]

@bijington - I've never seen any detached events logged in the reproduction solution, nor when calling the PopupService in our actual app, but they do occur in our actual solution when the page is navigated away from. PopupService must do something that's causing the behaviors to re-attach that's different than a standard dialog box / action sheet / etc.

[bijington]

When is the attached event logged? When you you click the 'Click me' button or the 'close' button?

[bengavin]

@bijington - when 'Click Me' is clicked [or shortly thereafter], it's while the popup is being displayed.

Thanks for the note on the ViewModel, that was during some DI troubleshooting of the sample and wasn't supposed to be there.

I've also verified that on both iOS simulator and Android emulator, the behavior does not seem to occur. The repro has been updated accordingly.

[bijington]

Thanks that is both interesting and helpful. It sounds like the approach we use to show the Popup on Windows might be triggering some lifecycle event which we don't want

[bijington]

I sadly don't have a working Windows environment right now so I can't look into it yet