allows to 'move' items in an IList object

extension method -- IList -- move

public static void Move<T>(this IList<T> list, int oldIndex, int newIndex)
{
    var item = list[oldIndex];

    list.RemoveAt(oldIndex);

    if (newIndex > oldIndex)
    {
        newIndex--;
    }
    // the actual index could have shifted due to the removal

    list.Insert(newIndex, item);
}