Moving ListViewItems Up & Down

Question

I have a ListView (WinForms) in which i want to move items up and down with the click of a button. The items to be moved are the ones who are checked. So if item 2, 6 and 9 are

Answer 1

This one is with wrapping, so if you move item at index 0 down it will come to last position, and if you move last item up it will be first on list:

    public static class ListExtensions
    {
        public static void MoveUp(this IList list, int index)
        {
            int newPosition = ((index > 0) ? index - 1 : list.Count - 1);
            var old = list[newPosition];
            list[newPosition] = list[index];
            list[index] = old;
        }

        public static void MoveDown(this IList list, int index)
        {
            int newPosition = ((index + 1 < list.Count) ? index + 1 : 0);
            var old = list[newPosition];
            list[newPosition] = list[index];
            list[index] = old;
        }
    }