[Accessibility] SubItems displayed incorrectly in Inspect or AccessibilityInsights after a column is removed from the ListView.

[Amy-Li03]

.NET version

.NET SDK 7.0.100-preview.7.22370.3

Did it work in .NET Framework?

Yes

Did it work in any of the earlier releases of .NET Core or .NET 5+?

1. This issue doesn't repro on .NET Core 3.1.
2. The subItems doesn't display in Inspect in .NET 5.0.
3. This issue all can reproduced on .NET 6.0 & 7.0.

Issue description

The SubItems displayed incorrectly in Inspect and Accessibility Insight tool after remove a column of ListView. .NET Core:

.NET Framework:

Steps to reproduce

1. Extract and open attached app: TestApp.zip
2. Build and run this app.
3. Launch Inspect or Accessibility Insight tool.
4. Focus on the subItems --- these subItems displayed correctly in Inspect.
5. Click "Remove Column" button.
6. Refresh Inspect tool.
7. Focus on the subItems --- these subItems displayed incorrectly in Inspect.

[dmitrii-drobotov]

This looks to be related to https://github.com/dotnet/winforms/issues/7481

[dmitrii-drobotov]

The bug exists because when a column is removed, the corresponding subitems are not deleted and still stored in the same order. A way to fix it is to recreate the handle of ListView after column removal. After that the visible content will be the same as in Inspect/Narrator but it does affect the behavior.

Right now column removal behavior looks logical but there would be a problem if something triggers recreation of ListView's handle. There are multiple operations that do it, for example, I've made a button that executes listView1.Scrollable = !listView1.Scrollable; which internally calls RecreateHandle() and as a result it indirectly changes the subitems.

In .NET Framework it's also the same.

If we add a call to RecreateHandle() after column removal, it will fix above problem and also the Inspect/Narrator issue:

I think it's more correct but I'm not sure if it's worth changing the behavior.

@merriemcgaw @Tanya-Solyanik what do you think, should we go with this solution (2nd gif)?

[merriemcgaw]

At this point I don't think it's the right time to change behavior, though I do think that may be the right approach. Let's put this on the back burner and consider for .NET 8.

[Tanya-Solyanik]

@merriemcgaw - I wouldn't recreate handle even in NET8 because is a breaking change that could manifest itself very subtly. @Amy-Li03 - does this repro for any other accessibility tools? Narrator in scan mode?

[Amy-Li03]

@Tanya-Solyanik Yes, Inspect, Accessibility Insights and Narrator (both narrator scan on and scan off) tools all can repro this issue.

[dmitrii-drobotov]

Ok, I see, thanks for the feedback! Maybe I could come up with a different solution then, and definitely later for .NET 8.

[NikitaSemenovAkvelon]

I've looked at this issue and can suggest few options to fix it:

1. Delete the SubItem on removing a column. In this way, we can save the consistency between columns and sub items. Moreover, it looks like a native control works in the same way because LVM.SUBITEMHITTEST returns a shifted index. I mean that if you remove the column with the index = 1 and after that call HitTest from the same position you'll receive a response with the same iSubItem value as before despite the SubItem is different, but in WinForms ListViewItem.SubItems[1] will be skipped but still contained in the collection. Nevertheless, it may be a breaking change, probably. If someone realized their own application with an opportunity to remove and restore columns.
2. Add an indicator to SubItem such as Disabled/Deleted which will be set on column removing. If the value is true we will skip these SubItems in AccessibilityObject children. But the restoration of this value will remain on a user.
3. Add a link to a ColumnHeader in the ListViewSubItem and replace the mechanism of finding child AO from SubItemIndex to ColumnLink.

@Tanya-Solyanik what do you think?

[Ashley-Li]

Verified this issue from main branch of winforms repo, this issue have been fixed. Now the SubItems displayed correctly in Inspect tool after remove a column of ListView.