ListViewExtensions.SmoothScrollIntoViewWithIndexAsync can throw a NullReferenceException if target SelectorItem is null

[Sergio0694]

Describe the bug

We recently hit a bug in the Microsoft Store where ListViewExtensions.SmoothScrollIntoViewWithIndexAsync can throw a NullReferenceException if target SelectorItem is null. The issue is this line:

WindowsCommunityToolkit/Microsoft.Toolkit.Uwp.UI/Extensions/ListViewBase/ListViewExtensions.SmoothScrollIntoView.cs

Line 77 in 77b009d

var transform = selectorItem.TransformToVisual((UIElement)scrollViewer.Content);

The issue is the returned selector can still be null, as ContainerFromIndex isn't guaranteed to return a not null value. This might happen in some weird corner cases eg. when a page is being unloaded or similar. The extension should likely just check that and do nothing if that's the case.

Regression

No

Windows Build Number

• Windows 10 1809 (Build 17763)
• Windows 10 1903 (Build 18362)
• Windows 10 1909 (Build 18363)
• Windows 10 2004 (Build 19041)
• Windows 10 20H2 (Build 19042)
• Windows 10 21H1 (Build 19043)
• Windows 11 21H2 (Build 22000)
• Other (specify)

Visual Studio Version

2022

Hello Sergio0694, thank you for opening an issue with us!

I have automatically added a "needs triage" label to help get things started. Our team will analyze and investigate the issue, and escalate it to the relevant team if possible. Other community members may also look into the issue and provide feedback 🙌