[Accessiblity] Narrator cannot announced the items correctly when switching the items by using up/down keyboard arrow that without expand the dropdown list panel

[MelonWang1]

.NET version

.NET SDK 10.0.100-alpha.1.24553.3

Did it work in .NET Framework?

No

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

No, this issue cannot repro in .NET 3.1, can repro in .NET 5.0.

.NET 3.1:

Issue description

When switching the items by using up/down keyboard arrow that without expand the dropdown list panel, Narrator announced the FlatStyle/BoserStyle property item twice, the first time unread in its entirety.

narrtor.mp4

Expected behavior:
Compare with NVDA tool, Narrator should be read the FlatStyle/BoserStyle property item only once and in its entirety.

nvda.mp4

Steps to reproduce

1. Create a .NET Core Winforms project.
2. Add a Label and PropertyGrid controls in form designer.
3. Set the SelectedObject property to Label1 in propertyGrid1 control.
4. Build and run project.
5. Open Narrator tool and select FlatStyle/BoserStyle property in propertyGrid control.
6. Use keyboard up and down key to select property item.

More info:

1. The issue cannot reproduce on standard combobox control.
2. The issue also can reproduce with other properties.
3. This issue cannot repro in NVDA tool.

[Tanya-Solyanik]

@LeafShi1 - we can't backport the fix for the drop down closing only on ENTER until this issue is fixed as well.

[LeafShi1]

The root cause is here

winforms/src/System.Windows.Forms/src/System/Windows/Forms/Controls/TextBox/TextBoxBase.cs

Line 1740 in ef16383

PInvokeCore.SendMessage(this, PInvokeCore.EM_SETSEL, (WPARAM)s, (LPARAM)e);

but for the issue Narrator announced the FlatStyle/BoserStyle property item twice, I don't think this is a real bug.
The reason for this is that the option is highlighted after it is selected.

• The first announce means that the "Standard" item is selected
• The second announce means that the "Standard" item in the editTextBox is highlighted

The problem is obvious from the announce of the Cursor property.

If we want to solve this problem, we can only make the item selected without selecting it in the edit text box, the result is like below

For issue the first time unread in its entirety, it should be fixed in PR #12431, once the edit text box gets the focus, the value can be read out completely.

@Tanya-Solyanik What do you think about this issue?

[Tanya-Solyanik]

@LeafShi1 - I added some comments in the PR.