protected override void OnSelected(RoutedEventArgs e)
{
base.OnSelected(e);
RequestBringIntoView += TreeViewItemEx_RequestBringIntoView;
if (Keyboard.IsKeyDown(Key.LeftShift) || Keyboard.IsKeyDown(Key.RightShift))
{
ItemsControl items = ParentItemsControl;
bool hasMultipleSelected = false;
foreach (object item in items.Items)
{
TreeViewItemEx ex = items.ItemContainerGenerator.ContainerFromItem(item) as TreeViewItemEx;
if (ex != null &&
ex.IsMultipleSelected)
{
hasMultipleSelected = true;
break;
}
}
if (hasMultipleSelected)
{
ParentTreeView.HandlingMultipleSelected = true;
bool select = false;
foreach (object item in items.Items)
{
TreeViewItemEx ex = items.ItemContainerGenerator.ContainerFromItem(item) as TreeViewItemEx;
if (ex == null)
{
continue;
}
if (select)
{
if (ReferenceEquals(ex, this) ||
ex.IsMultipleSelected)
{
ex.IsMultipleSelected = true;
break;
}
ex.IsMultipleSelected = true;
}
else
{
if (ReferenceEquals(ex, this) ||
ex.IsMultipleSelected)
{
ex.IsMultipleSelected = true;
select = true;
}
}
}
}
}
else
{
ParentTreeView?.ClearMultipleSelection();
IsMultipleSelected = true;
if (ParentTreeView != null)
{
ParentTreeView.HandlingMultipleSelected = true;
}
}
}