[Windows] Adding Items to ObservableCollection from other UIThread in ListView Throws System.Runtime.InteropServices.COMException

[LogishaSelvarajSF4525]

Description

Description

In .NET MAUI, a System.Runtime.InteropServices.COMException is encountered when adding data to a shared ObservableCollection (staticData.TestCollection) from a background thread. This problem is specific to the Windows platform, as ObservableCollection requires all operations to be performed on the same thread on which it was created, typically the UI thread, and does not support cross-thread modifications.

This issue occurs exclusively on the Windows platform and does not affect other platforms.

Note: While fixing this issue enable the following UITest in HostApp: Issue6472

In Windows,

Steps to Reproduce

1. Run the application with attached code on the Windows platform. MauiApp1.zip

Expected Behavior:

• Items should be successfully added to the ObservableCollection without throwing any exceptions.
• The ListView should update to display the new items added from the background thread.

Actual Behavior:

• A runtime exception is thrown, indicating that the ObservableCollection cannot be modified from a thread other than the one it was created on.
• The ListView does not update, and the application may crash depending on how the exception is handled.

Link to public reproduction project repository

No response

Version with bug

9.0.12 SR1.2

Is this a regression from previous behavior?

Not sure, did not test other versions

Last version that worked well

Unknown/Other

Affected platforms

Windows

Affected platform versions

No response

Did you find any workaround?

No response

Relevant log output

[dotnet-policy-service]

Hi @LogishaSelvarajSF4525. We have added the "s/try-latest-version" label to this issue, which indicates that we'd like you to try and reproduce this issue on the latest available public version. This can happen because we think that this issue was fixed in a version that has just been released, or the information provided by you indicates that you might be working with an older version.

You can install the latest version by installing the latest Visual Studio (Preview) with the .NET MAUI workload installed. If the issue still persists, please let us know with any additional details and ideally a reproduction project provided through a GitHub repository.

This issue will be closed automatically in 7 days if we do not hear back from you by then - please feel free to re-open it if you come back to this issue after that time.

[RoiChen001]

I verified this issue on the latest 17.13 Preview 2.1(9.0.30 & 9.0.12) Windows platform, but no exception was thrown.

[nivetha-nagalingam]

In Issue 6994 from HostApp, the same exception System.Runtime.InteropServices.COMException was also occurring, as detailed in the file located at https://github.com/dotnet/maui/blob/main/src/Controls/tests/TestCases.HostApp/Issues/Issue6994.cs

ListViewCrash6994.mp4