Microsoft.Phone.Controls.ContextMenu.FocusNextItem C# (CSharp) Method

        private void FocusNextItem(bool down)
        {
            int count = Items.Count;
            int startingIndex = down ? -1 : count;
            MenuItem focusedMenuItem = FocusManager.GetFocusedElement() as MenuItem;
            if (null != focusedMenuItem && (this == focusedMenuItem.ParentMenuBase))
            {
                startingIndex = ItemContainerGenerator.IndexFromContainer(focusedMenuItem);
            }
            int index = startingIndex;
            do
            {
                index = (index + count + (down ? 1 : -1)) % count;
                MenuItem container = ItemContainerGenerator.ContainerFromIndex(index) as MenuItem;
                if (null != container)
                {
                    if (container.IsEnabled && container.Focus())
                    {
                        break;
                    }
                }
            }
            while (index != startingIndex);
        }