fixed the closed button displaying bug

[CipherPol9]

Description

Added UpdateCloseButton() under TabViewItem::OnApplyTemplate()

Motivation and Context

fixes the issue of the close button showing up on the video tab because the TabViewItem was depending on the onloaded event handler to set the close button visibility but this would fail if the template hasn't been applied yet. Fixes #1416

How Has This Been Tested?

Manually

Screenshots (if appropriate):

[msftclas]

All CLA requirements met.

[StephenLPeters]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[StephenLPeters]

UpdateCloseButton();

I think that the UpdateCloseButton() call in OnApplyTemplate() might cover all the scenarios we are interested in. Can you try deleting this OnLoaded event handler and seeing if it still behaves as intended?

---

Refers to: dev/TabView/TabViewItem.cpp:113 in c003f69. [](commit_id = c003f69, deletion_comment = False)

[StephenLPeters]

Adding a new test to ensure this functionality would be great

[StephenLPeters]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[jevansaks]

Please use an override that takes a TimeSpan to make this more readable (so I don't have to go to the docs to see what this does 🙂).

Suggested change

	await Task.Delay(1);
	await Task.Delay(TimeSpan.FromMilliseconds(1));

[jevansaks]

@CipherPol9 do you think you'll be able to incorporate these changes?

[wbokkers]

Any change of this PR to be changed and reviewed? There's only a minor change needed in the test code (and not in the fix itself).

[StephenLPeters]

Any change of this PR to be changed and reviewed? There's only a minor change needed in the test code (and not in the fix itself).

I asked for a product code change, and a new test would be great. @CipherPol9 Do you think you'll be able to address the feedback? If not we should take over this change. @teaP have you taken a look?

[StephenLPeters]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[StephenLPeters]

@jevansaks @teaP maybe take another look with my amendment?

[msft-github-bot]

🎉Microsoft.UI.Xaml v2.3.191211002 has been released which incorporates this pull request.:tada:

Handy links:

• Release Notes
• Official Nuget Release