private void OnNavigationKey(TreeViewItemEx targetContainer)
{
if (targetContainer == null)
{
return;
}
if (IsControlDown)
{
targetContainer.FocusWithRetry();
targetContainer.BringIntoView();
}
else
{
MoveSelection(targetContainer);
}
}
internal void MoveSelection(TreeViewItemEx container)
{
Debug.Assert(container != null);
var selectedItems = SelectedItems;
if (selectedItems != null)
{
var item = container.Item;
if (selectedItems.Count == 1 && selectedItems[0] == item)
{
// Focused moved back to current and only selected item.
_shiftSelectionAnchor = container;
}
else if (IsControlDown)
{
// Ctrl-click item toggles selection.
if (selectedItems.Contains(item))
{
selectedItems.Remove(item);
}
else
{
selectedItems.Add(item);
}
_shiftSelectionAnchor = container;
}
else if (IsShiftDown && selectedItems.Count > 0)
{
// Shift-click extends selection.
var anchorContainer = _shiftSelectionAnchor ?? GetContainer(selectedItems[0]);
var rangeItems = GetRangeItems(this, anchorContainer, container, true);
for (int i = selectedItems.Count - 1; i >= 0; i--)
{
if (!rangeItems.Contains(selectedItems[i]))
{
selectedItems.RemoveAt(i);
}
}
for (int i = 0; i < rangeItems.Count; i++)
{
if (!selectedItems.Contains(rangeItems[i]))
{
selectedItems.Add(rangeItems[i]);
}
}
}
else
{
// Single selection.
for (int i = selectedItems.Count - 1; i >= 0; i--)
{
if (selectedItems[i] != item)
{
selectedItems.RemoveAt(i);
}
}
if (!selectedItems.Contains(item))
{
selectedItems.Add(item);
}
_shiftSelectionAnchor = container;
}
}
container.FocusWithRetry();
container.BringIntoView();
}