private void UpdateSelectedItems(TreeListViewItem viewItem)
{
if (viewItem.IsSelected)
{
if (!_selectedItems.Contains(viewItem))
_selectedItems.Add(viewItem);
}
else
{
_selectedItems.Remove(viewItem);
}
}
private void ExtendSelectionTo(TreeListViewItem rangeSelectionEnd)
{
//if _rangeSelectionStart == null then it is just a single select so: _rangeSelectionStart=rangeSelectionEnd
if (_rangeSelectionStart == null)
{
_rangeSelectionStart = rangeSelectionEnd;
UpdateSelectedItems(rangeSelectionEnd);
}
else
{
//SelectAllItemsBetween _rangeSelectionStart and rangeSelectionEnd
var descendants = Descendants()
//Filter out parent rows, unless a parent row was explicitly selected.
.Where(child =>
CanUpdateParents
|| child.ParentTreeListViewItem != null
|| ReferenceEquals(child, _rangeSelectionStart)
|| ReferenceEquals(child, rangeSelectionEnd))
.ToList();
var startIdx = descendants.IndexOf(_rangeSelectionStart);
var endIdx = descendants.IndexOf(rangeSelectionEnd);
if (startIdx > endIdx)
{
endIdx = Interlocked.Exchange(ref startIdx, endIdx);
}
var lastRangeSelection = _rangeSelection.ToArray().ToList();
_rangeSelection.Clear();
using (SupressSelectionHandler())
{
for (int i = startIdx; i <= endIdx; i++)
{
var item = descendants[i];
if (!item.IsSelected || ReferenceEquals(item, rangeSelectionEnd))
{
item.IsSelected = true;
UpdateSelectedItems(item);
_rangeSelection.Add(item);
}
lastRangeSelection.Remove(item);
}
foreach (var oldItem in lastRangeSelection)
{
oldItem.IsSelected = false;
UpdateSelectedItems(oldItem);
}
}
}
}
private void SelectSingleItem(TreeListViewItem viewItem)
{
var selectedItems = Descendants()
.Where(child => child.IsSelected
&& !ReferenceEquals(child, viewItem)
&& (CanUpdateParents || child.ParentTreeListViewItem != null))
.ToList();
var isSelected = viewItem.IsSelected;
using (SupressSelectionHandler())
{
foreach (var selectedItem in selectedItems)
{
selectedItem.IsSelected = false;
UpdateSelectedItems(selectedItem);
}
//Ensure that modifications to other items have not unselected this item.
viewItem.IsSelected = isSelected;
}
UpdateSelectedItems(viewItem);
}
internal void OnItemSelected(TreeListViewItem viewItem)
{
if (viewItem == null || IgnoreSelectionChanged())
return;
if (Keyboard.IsKeyDown(Key.LeftShift) || Keyboard.IsKeyDown(Key.RightShift))
{
ExtendSelectionTo(viewItem);
}
else
{
_rangeSelection.Clear();
if (Keyboard.IsKeyDown(Key.LeftCtrl) || Keyboard.IsKeyDown(Key.RightCtrl))
{
UpdateSelectedItems(viewItem);
}
else
{
SelectSingleItem(viewItem);
}
_rangeSelectionStart = viewItem.IsSelected ? viewItem : null;
}
}
/// <summary>
/// Retrieve the subsequent node that is at the same level.
/// </summary>
/// <param name="item">The node starting with you want to retrieve the subsequent one.</param>
/// <returns>Null if there is no subsequent node at the same level.</returns>
private static TreeListViewItem GetNextNodeAtSameLevel(TreeListViewItem item)
{
if (item == null)
return null;
TreeListViewItem nextNodeAtSameLevel = null;
var parentControl = item.ParentItemsControl;
if (parentControl != null)
{
int index = parentControl.ItemContainerGenerator.IndexFromContainer(item);
if (index != parentControl.Items.Count - 1) // if this is not the last item
{
nextNodeAtSameLevel = parentControl.ItemContainerGenerator.ContainerFromIndex(index + 1) as TreeListViewItem;
}
}
return nextNodeAtSameLevel;
}
/// <summary>
/// Retrieve the last displayed child node of the given one.
/// </summary>
/// <param name="item">The node starting with you want to retrieve the last visible node.</param>
/// <returns>The last child node that is displayed, or the node itself in case it is not expanded.</returns>
private static TreeListViewItem GetLastVisibleChildNodeOf(TreeListViewItem item)
{
var lastVisibleNode = item;
// Retrieving last child of last expanded node
while (lastVisibleNode != null && lastVisibleNode.Items.Count > 0 && lastVisibleNode.IsExpanded)
lastVisibleNode = lastVisibleNode.ItemContainerGenerator.ContainerFromIndex(lastVisibleNode.Items.Count - 1) as TreeListViewItem;
return lastVisibleNode;
}
