CsDebugScript.UI.InteractiveResultVisualizer.Tree_PreviewKeyDown C# (CSharp) Method

        private void Tree_PreviewKeyDown(object sender, KeyEventArgs e)
        {
            if (e.Key == Key.Down && e.KeyboardDevice.Modifiers == ModifierKeys.None)
            {
                TreeView tree = (TreeView)sender;
                TreeViewItem item = e.OriginalSource as TreeViewItem;

                // if item is expanded and has items, then this item is not the last one :)
                if (item.HasItems && item.IsExpanded)
                    return;

                // Check inside the parent
                TreeViewItem parent = item.Parent as TreeViewItem;

                while (parent != null)
                {
                    if (parent.Items.IndexOf(item) == parent.Items.Count - 1)
                    {
                        parent = parent.Parent as TreeViewItem;
                    }
                    else
                    {
                        // We are not at the last item
                        return;
                    }
                }

                e.Handled = true;
                tree.MoveFocus(new TraversalRequest(FocusNavigationDirection.Next));
            }
            else if (e.Key == Key.Up && e.KeyboardDevice.Modifiers == ModifierKeys.None)
            {
                TreeView tree = (TreeView)sender;
                TreeViewItem item = e.OriginalSource as TreeViewItem;

                // Check inside the parent
                TreeViewItem parent = item.Parent as TreeViewItem;

                if (parent != null || tree.Items.IndexOf(item) > 1) // 1 is because of the header
                {
                    // We are not at the first item
                    return;
                }

                e.Handled = true;
                tree.MoveFocus(new TraversalRequest(FocusNavigationDirection.Previous));
            }
        }