[Bug] Adding tabs to the TabViewItems after constructing it does not update Carousel

[adammeaney]

Description

If you make a TabView that uses the TabItems property, not the TabItemsSource, you cannot add tabs at runtime and then navigate to them.

The tab strip updates, but the CarouselView does not add the new TabItem Content to its ItemsSource at any time.

Steps to Reproduce

1. Make a page with TabItems
2. Add an item using a button on the page
3. Click the tab in the strip, see it not load the Content you expected.

Expected Behavior

Tabs can be added at runtime to the TabItems

Actual Behavior

Tabs are ignored at runtime, and only produce a tab strip item.

Basic Information

• Version with issue: Commit 43b8dbd
• Last known good version: Never
• IDE: VS 2019 16.7.7
• Platform Target Frameworks: Not relevant, Toolkit Forms code problem
  • iOS:
  • Android:
  • UWP:
• Android Support Library Version:
• Nuget Packages:
• Affected Devices:

Workaround

Use TabItemsSource, as there are listeners that actually do real things on it. The code for UpdateTabItems doesn't touch the carousel.

Reproduction imagery

Reproduction Link

adammeaney@b7eb974

[adammeaney]

As a side note I can open in a different issue if needed, but semi-related as its an add problem, if we add a tab item, you set the selected tab to the first one every time. Seems rather silly. I would much prefer to stay on the tab I am on.

[adammeaney]

I will say that after more testing, similar things happen when using the TabItemsSource as well.

This is a gif of me trying a similar approach with TabItemsSource and DataTemplates instead.

Its not exactly the same, but I will say I think the rendering of this TabView is lacking for handling updates appropriately.

Both TabItems and TabItemsSource use code that just doesnt update well. The same screens look fine if I define everything before it gets drawn on the screen, but async code is just not handled right.

[albilaga]

Any update on this @jsuarezruiz ? I also have this issue. If need more repro here it is https://github.com/albilaga/XamarinIssues/blob/main/XamarinIssues/TabViews/MainTabCreatePage.xaml.cs. Note is if adding TabItems in constructor is working fine but not in OnAppearing