internal void HandleCollapse(TreeViewItemEx container)
{
Debug.Assert(container != null);
// Unselect all collapsed items.
bool childFocused = false;
bool childSelected = false;
foreach (var childContainer in GetAllContainers(container, true))
{
if (childContainer.IsKeyboardFocusWithin)
{
childFocused = true;
}
if (childContainer.IsSelected)
{
childSelected = true;
childContainer.IsSelected = false;
}
}
if (childSelected)
{
MoveSelection(container);
}
else if (childFocused)
{
container.FocusWithRetry();
}
}
internal void HandleGotFocus(TreeViewItemEx container)
{
if (container != null)
{
// Initial selection.
var selectedItems = SelectedItems;
if (selectedItems != null && selectedItems.Count == 0)
{
MoveSelection(container);
}
}
if (_lastFocusedContainer == container)
{
return;
}
if (_lastFocusedContainer != null)
{
_lastFocusedContainer.IsTabStop = false;
}
_lastFocusedContainer = container;
if (_lastFocusedContainer != null)
{
_lastFocusedContainer.IsTabStop = true;
}
IsTabStop = (_lastFocusedContainer == null);
}
private static TreeViewItemEx GetNextContainer(TreeViewItemEx current, bool onlyVisible)
{
if (current == null)
{
return(null);
}
if (current.HasItems && (!onlyVisible || current.IsExpanded))
{
return(current.ItemContainerGenerator.ContainerFromIndex(0) as TreeViewItemEx);
}
do
{
var sibling = GetNextSibling(current);
if (sibling != null)
{
return(sibling);
}
current = current.ParentTreeViewItem;
} while (current != null);
return(null);
}
internal void HandleKeyDown(TreeViewItemEx container, KeyEventArgs e)
{
// TODO: Consider FlowDirection for Left/Right.
switch (e.Key)
{
case Key.Home:
OnNavigationKey(GetFirstContainer(this, true));
e.Handled = true;
break;
case Key.End:
OnNavigationKey(GetLastContainer(this, true));
e.Handled = true;
break;
case Key.Up:
OnNavigationKey(GetPreviousContainer(container ?? GetFocusedContainer(), true));
e.Handled = true;
break;
case Key.Down:
OnNavigationKey(GetNextContainer(container ?? GetFocusedContainer(), true));
e.Handled = true;
break;
case Key.PageUp:
OnNavigationKey(GetPageUpDownContainer(container ?? GetFocusedContainer(), false));
e.Handled = true;
break;
case Key.PageDown:
OnNavigationKey(GetPageUpDownContainer(container ?? GetFocusedContainer(), true));
e.Handled = true;
break;
case Key.Left:
OnNavigationKey((container ?? GetFocusedContainer())?.ParentTreeViewItem);
e.Handled = true;
break;
case Key.A:
if (e.KeyboardDevice.Modifiers == ModifierKeys.Control)
{
SelectAll();
e.Handled = true;
}
break;
case Key.Space:
MoveSelection(container ?? GetFocusedContainer());
e.Handled = true;
break;
}
}
private TreeViewItemEx GetPageUpDownContainer(TreeViewItemEx container, bool down)
{
if (container == null)
{
return(down ? GetLastContainer(this, true) : GetFirstContainer(this, true));
}
double yThreshold = container.TransformToAncestor(this).Transform(new Point()).Y;
double itemHeight = container.HeaderHeight;
double viewportHeight = _scrollViewer?.ViewportHeight ?? ActualHeight;
double offset = viewportHeight - 2 * itemHeight;
if (down)
{
yThreshold += offset;
var nextContainer = GetNextContainer(container, true);
while (nextContainer != null)
{
container = nextContainer;
double y = container.TransformToAncestor(this).Transform(new Point()).Y;
if (y > yThreshold)
{
break;
}
nextContainer = GetNextContainer(nextContainer, true);
}
}
else
{
yThreshold -= offset;
var previousContainer = GetPreviousContainer(container, true);
while (previousContainer != null)
{
container = previousContainer;
double y = container.TransformToAncestor(this).Transform(new Point()).Y;
if (y < yThreshold)
{
break;
}
previousContainer = GetPreviousContainer(previousContainer, true);
}
}
return(container);
}
private void OnNavigationKey(TreeViewItemEx targetContainer)
{
if (targetContainer == null)
{
return;
}
if (IsControlDown)
{
targetContainer.FocusWithRetry();
targetContainer.BringIntoView();
}
else
{
MoveSelection(targetContainer);
}
}
private static TreeViewItemEx GetNextSibling(TreeViewItemEx current)
{
Debug.Assert(current != null);
var itemsControl = current.ParentItemsControl;
Debug.Assert(itemsControl != null, "Item container expected to be part of TreeViewEx.");
int index = itemsControl.ItemContainerGenerator.IndexFromContainer(current);
Debug.Assert(0 <= index && index < itemsControl.Items.Count, "Invalid index.");
int nextIndex = index + 1;
return((nextIndex < itemsControl.Items.Count)
? itemsControl.ItemContainerGenerator.ContainerFromIndex(nextIndex) as TreeViewItemEx
: null);
}
private static TreeViewItemEx GetPreviousContainer(TreeViewItemEx current, bool onlyVisible)
{
if (current == null)
{
return(null);
}
var sibling = GetPreviousSibling(current);
if (sibling != null)
{
if (sibling.HasItems && (!onlyVisible || sibling.IsExpanded))
{
return(GetLastContainer(sibling, onlyVisible));
}
return(sibling);
}
return(current.ParentTreeViewItem);
}
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();
}
private static List <object> GetRangeItems(ItemsControl itemsControl, TreeViewItemEx first, TreeViewItemEx last, bool onlyVisible)
{
var containers = GetRangeContainers(itemsControl, first, last, onlyVisible);
return(containers.Select(c => c.Item).ToList());
}
private static List <TreeViewItemEx> GetRangeContainers(ItemsControl itemsControl, TreeViewItemEx first, TreeViewItemEx last, bool onlyVisible)
{
Debug.Assert(first != null);
Debug.Assert(last != null);
var list = new List <TreeViewItemEx>();
if (first == last)
{
list.Add(first);
return(list);
}
using (var enumerator = GetAllContainers(itemsControl, onlyVisible).GetEnumerator())
{
while (enumerator.MoveNext())
{
if (enumerator.Current == first || enumerator.Current == last)
{
list.Add(enumerator.Current);
break;
}
}
while (enumerator.MoveNext())
{
list.Add(enumerator.Current);
if (enumerator.Current == first || enumerator.Current == last)
{
break;
}
}
}
Debug.Assert(list.Count > 0);
if (list[0] != first)
{
list.Reverse();
}
Debug.Assert(list[0] == first);
Debug.Assert(list[list.Count - 1] == last);
return(list);
}