[MAUI] I4_ Selection - Click the 'Single pre-selection for Vertical list ' item will throw an exception: Object reference not set to an instance of an object

dotnet / maui

.NET MAUI is the .NET Multi-platform App UI, a framework for building native device applications spanning mobile, tablet, and desktop.

MIT License

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Description

Affected case: I4:Single Pre-selection (Vertical list)

Steps to Reproduce

Deploy https://devdiv.visualstudio.com/Pkgs/_git/VS.TestAssets.Xaml?path=/Assets/Projects/ManualMauiTests to Windows.
Navigate to 'I CollectionView' ->'I4 Selection '
Open Single Pre-selection (Vertical list) page.

Actual Behavior:

Expected Behavior: Open normally

Link to public reproduction project repository

https://devdiv.visualstudio.com/Pkgs/_git/VS.TestAssets.Xaml?path=/Assets/Projects/ManualMauiTests

Version with bug

Microsoft.Maui.Controls 8.0.70-ci.net8.24328.1

Is this a regression from previous behavior?

Not a regression, the issue also repro on 8.0.61& 8.0.3

Affected platforms

Windows

Relevant log output

System.NullReferenceException
  HResult=0x80004003
  Message=Object reference not set to an instance of an object.
  Source=ManualMauiTests
  StackTrace:
   at ManualMauiTests.ViewModels.MonkeysViewModel.MonkeySelectionChanged() in C:\Users\admin\Desktop\ManualMauiTests\ManualMauiTests\ViewModels\MonkeysViewModel.cs:line 232

Hi I'm an AI powered bot that finds similar issues based off the issue title.

Please view the issues below to see if they solve your problem, and if the issue describes your problem please consider closing this one and thumbs upping the other issue to help us prioritize it. Thank you!

Open similar issues:

[MAUI] I4_ Selection - Selected items are not highlighted (#23296), similarity score: 0.79
[MAUI] I4_ Selection - The default items not highlight in Single Pre-selection and Multiple Pre-selection Page (#23299), similarity score: 0.75
[MAUI] I6 Grouping - 'Grouping for Vertical list without DataTemplates' page loading exception (#23293), similarity score: 0.73
[MAUI] I CollectionView - After selecting an item in a subpage once, you cannot select any other items when you back (#23295), similarity score: 0.71

Closed similar issues:

MVVM ObservableCollection SelectedItem = null = Exception (#8329), similarity score: 0.71

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dotnet / maui