ListView.Items.RemoveAt causes NullReferenceException

• .NET Core Version: 6.0.0

• Have you experienced this same bug with .NET Framework?: Classic .NET - No .NET 5 - No .NET 6 - Yes

Problem description: Deleting a selected item from ListView causes NullReferenceException on calling ListView.Items.RemoveAt(index). The bug reproduces stable in my app in the following conditions:

1. The item being deleted must be selected. If it’s not selected, no error.
2. To workaround the error, we can call ListView.Focus() before delete.
3. ListView is a Details view.

The code that fails: `

// listView1.Focus(); // helps to avoid error

listView1.Items.RemoveAt(0); // error is here if item 0 is selected

MessageBox.Show("a"); // shows after error

`

Despite the error, the item is deleted.

Error stack: System.NullReferenceException: Object reference not set to an instance of an object. at System.Windows.Forms.ListViewItem.get_AccessibilityObject() at System.Windows.Forms.ListView.ListViewAccessibleObject.GetFocus() at System.Windows.Forms.ListView.OnGotFocus(EventArgs e) at System.Windows.Forms.Control.WmSetFocus(Message& m) at System.Windows.Forms.Control.WndProc(Message& m) at System.Windows.Forms.ListView.WndProc(Message& m) at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m) at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, WM msg, IntPtr wparam, IntPtr lparam)

Expected behavior: No error in the above case. Because it worked well before .NET 6.

Minimal repro: I couldn’t create a small app to reproduce the error, because there is no error in a simple app. However, I hope that a developer who works daily on WinForms, can find the possible mistake in ListViewItem.get_AccessibilityObject() Edit: the test app is attached below.

[RussKie]

@vladimir-krestov @SergeySmirnov-Akvelon please investigate

[msftbot[bot]]

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