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bug: exception when using ListViewItemSorter

See original GitHub issue

Following code throws an exception, while it works fine in .NET 4.8 I use .NET 5.0 latest SDK and latest VS 2019 community. I’m using a WinForms application .NET 5.0

WHEN: The exception is thrown when you click the same column header the THIRD time (first and second time it works and no exception thrown).

WHAT: Exception thrown: ‘System.NullReferenceException’ in System.Windows.Forms.dll Object reference not set to an instance of an object.

WHERE: Exception thrown on code line: listViewCardSets.ListViewItemSorter = new ListViewItemStringComparer(e.Column, listViewCardSets.Sorting);

class ListViewItemStringComparer : IComparer
    {
        private int col;
        private SortOrder order;
        public ListViewItemStringComparer()
        {
            col = 0;
            order = SortOrder.Ascending;
        }

        public ListViewItemStringComparer(int column, SortOrder order)
        {
            col = column;
            this.order = order;
        }

        public int Compare(object x, object y)
        {
            int returnVal = -1;
            returnVal = String.Compare(((ListViewItem)x).SubItems[col].Text,
                                       ((ListViewItem)y).SubItems[col].Text);

            // Determine whether the sort order is descending.
            if (order == SortOrder.Descending)
                // Invert the value returned by String.Compare.
                returnVal *= -1;

            return returnVal;
        }
    }

        private int _sortColumnIndex = -1;
        private void listViewCardSets_ColumnClick(object sender, ColumnClickEventArgs e)
        {
            // Determine whether the column is the same as the last column clicked.
            if (e.Column != _sortColumnIndex)
            {
                // Set the sort column to the new column.
                _sortColumnIndex = e.Column;
                // Set the sort order to ascending by default.
                listViewCardSets.Sorting = SortOrder.Ascending;
            }
            else
            {
                // Determine what the last sort order was and change it.
                if (listViewCardSets.Sorting == SortOrder.Ascending)
                    listViewCardSets.Sorting = SortOrder.Descending;
                else
                    listViewCardSets.Sorting = SortOrder.Ascending;
            }

            // Call the sort method to manually sort.
            listViewCardSets.Sort();

            // Set the ListViewItemSorter property to a new ListViewItemComparer object.
            listViewCardSets.ListViewItemSorter = new ListViewItemStringComparer(e.Column, listViewCardSets.Sorting);
        }