private List <MultiSelectTreeViewItem> GetTreeViewItemRange(
MultiSelectTreeViewItem start,
MultiSelectTreeViewItem end)
{
List <MultiSelectTreeViewItem> items = GetTreeViewItems(this, false);
int startIndex = items.IndexOf(start);
int endIndex = items.IndexOf(end);
int rangeStart = startIndex > endIndex || startIndex == -1 ? endIndex : startIndex;
int rangeCount = startIndex > endIndex ? startIndex - endIndex + 1 : endIndex - startIndex + 1;
if (startIndex == -1 && endIndex == -1)
{
rangeCount = 0;
}
else if (startIndex == -1 || endIndex == -1)
{
rangeCount = 1;
}
return(rangeCount > 0 ? items.GetRange(rangeStart, rangeCount) : new List <MultiSelectTreeViewItem>());
}
protected override void OnPreviewMouseUp(MouseButtonEventArgs e)
{
base.OnPreviewMouseUp(e);
// If clicking on a tree branch expander...
if (InExpanderTree(e.OriginalSource))
{
return;
}
MultiSelectTreeViewItem item = GetTreeViewItemClicked((FrameworkElement)e.OriginalSource);
if (item != null)
{
if (e.ChangedButton == MouseButton.Left && item == mouseDownItem)
{
SelectedItemChangedInternal(item);
item.IsSelected = true;
}
}
}
private void SelectedItemChangedInternal(MultiSelectTreeViewItem tvItem)
{
// Clear all previous selected item states if ctrl is NOT being held down
if (!IsCtrlPressed)
{
List <MultiSelectTreeViewItem> items = GetTreeViewItems(this, true);
foreach (MultiSelectTreeViewItem treeViewItem in items)
{
SetIsItemSelected(treeViewItem, false);
}
}
// Is this an item range selection?
if (IsShiftPressed)
{
if (_lastItemSelected == null)
{
// Otherwise, individual selection
SetIsItemSelected(tvItem, true);
_lastItemSelected = tvItem;
}
else
{
List <MultiSelectTreeViewItem> items = GetTreeViewItemRange(_lastItemSelected, tvItem);
if (items.Count > 0)
{
foreach (MultiSelectTreeViewItem treeViewItem in items)
{
if (OneSelectedItem == null ||
treeViewItem.Header.GetType() == OneSelectedItem.Header.GetType())
{
SetIsItemSelected(treeViewItem, true);
}
}
_lastItemSelected = items.Last();
}
}
}
else if (IsCtrlPressed)
{
//Deselect if it's selected
if (GetIsItemSelected(tvItem))
{
SetIsItemSelected(tvItem, false);
_lastItemSelected = tvItem;
}
else if (OneSelectedItem == null ||
OneSelectedItem.Header.GetType() == tvItem.Header.GetType())
{
//Select it if it's on its own, or matches the tier of the other selected items
SetIsItemSelected(tvItem, true);
_lastItemSelected = tvItem;
}
}
else
{
// Otherwise, individual selection
SetIsItemSelected(tvItem, true);
_lastItemSelected = tvItem;
}
}