public static void ReverseSelections(this ListViewBase listView)
{
if (listView.SelectedItems.Count == 0)
{
listView.SelectAll();
return;
}
if (listView.SelectedItems.Count == listView.Items.Count)
{
listView.ClearSelections();
return;
}
var selected = listView.SelectedItems.ToHashSet();
listView.SelectedItems.Clear();
foreach (var item in selected)
{
if (!selected.Contains(item))
{
listView.SelectedItems.Add(item);
}
}
}