NavigationView crashes when collapsing/expanding after modifying items dynamically

[Georgios1999]

Describe the bug

When dynamically updating items (adding new items in the NavigationView or inside other NavigationViewItems, removing, or editing (renaming, changing properties) these items) and refreshing there is a seemingly random chance that the program will crash after collapsing the Navigation View with this error:

Exception thrown at 0x00007FFA38F366CA in Workflow.exe: Microsoft C++ exception: winrt::hresult_error at memory location 0x000000B7399D7240.

The debugger redirects me to App.i.g.cs (note that this file has remained unchanged). Specifically, it highlights these lines:

global::Microsoft.UI.Xaml.Application.Start((p) => {
    var context = new global::Microsoft.UI.Dispatching.DispatcherQueueSynchronizationContext(global::Microsoft.UI.Dispatching.DispatcherQueue.GetForCurrentThread());
    global::System.Threading.SynchronizationContext.SetSynchronizationContext(context);
    new App();
});

Note

You might need to check "Win32 exceptions" and "Common Language Runtime Exceptions" in Visual Studio's Exception Settings to see this. Otherwise, the debugger redirects to global::System.Diagnostics.Debugger.Break(); in App.i.g.cs with no error.

Why is this important?

My specific use case:
I'm making a productivity app, where the user can create Workspaces and Folders contained within these Workspaces. The Folders can also be customized so it's easier to organize them using colors, icons, etc. The navigation between Workspaces and Folders is done through a NavigationView, since it's the most user-friendly and straightforward way to navigate between pages like this, and its built-in tree-like structure makes it easy to group pages.

Adding, removing or editing items in a NavigationView has numerous other use cases, like for file explorers, item lists, etc. I find it a core feature of an app like this, so I consider this bug to be important enough.

Steps to reproduce the bug

1.Create a NavigationView with a NavigationViewItem (example “Workspaces”) that contains subitems.
2. Dynamically add/remove subitems using code-behind (e.g., by enumerating folders in ApplicationData.Current.LocalFolder).
3. Open the app, expand/collapse the NavigationView.
4. After editing/deleting/renaming a workspace, collapse the NavigationView pane → crash.

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I have made a minimal reproduction project in this repository: https://github.com/Georgios1999/NavViewCrashRepro.git

Build it in Visual Studio 2022, test it by adding, removing, recoloring, editing workspaces and folders and as you do, try to collapse the Navigation View by clicking this built-in button:

The app should eventually crash. This doesn’t always happen immediately, but after a few refresh cycles (add/remove/recolor + collapse/expand), the crash reliably occurs.

Actual behavior

App crashes with an unhandled winrt::hresult_error inside Microsoft.UI.Xaml.dll when collapsing/expanding the NavigationView. (See details and additional info for more info)

Expected behavior

The NavigationView collapses as expected.

Screenshots

No response

NuGet package version

WinUI 3 - Windows App SDK 1.7.3: 1.7.250606001

Windows version

Windows Insider Build (xxxxx)

Additional context

Debug also shows

Microsoft.UI.Xaml.dll!00007FF9D855A6FF: 80004005 - Unspecified error
Exception thrown at 0x00007FFA38F366CA (KernelBase.dll) in Workflow.exe: WinRT originate error - 0x80004005 : 'Unspecified error'.

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Extra info:

Windows SDK: 10.0.26100.4654
IDE: Visual Studio 2022 (latest stable)
Target framework: net8.0-windows10.0.19041.0

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Note

The same exception is mentioned in #9538 but I decided to create this issue to submit more info and to document what happens in my use case. Thought that would help. If not, feel free to close this issue.