private void AutoScrollToItem(Point currentPosition, FrameworkElement targetItem)
{
IList items = GetItems(TargetElement);
if (TargetElement is ListBox && items != null && items.Count > 0)
{
ListBox listBox = TargetElement as ListBox;
if (targetItem != null)
{
FrameworkElement itemsPanel = VisualTreeHelper.GetParent(targetItem) as FrameworkElement;
Point currentPositionRelativeItemsPanel = TargetElement.TranslatePoint(currentPosition, itemsPanel);
object item = targetItem.DataContext;
if (item == null)
{
item = targetItem;
}
int currentIndex = items.IndexOf(item);
if (currentPositionRelativeItemsPanel.Y < ScrollDataBound)
{
listBox.ScrollIntoView(items[Math.Max(0, currentIndex - 1)]);
}
else if (currentPositionRelativeItemsPanel.Y >= itemsPanel.ActualHeight - ScrollDataBound)
{
listBox.ScrollIntoView(items[Math.Min(items.Count - 1, currentIndex + 1)]);
}
}
}
}
protected override void OnDragStarted(double horizontalOffset, double verticalOffset)
{
TargetLayer.GuidelineFilter.Push(GetSizeGuidableLines);
beginSize = (Vector)TargetElement.RenderSize;
if (TargetLayer.Parent is IStoryboard)
{
beginPosition = new Vector(
Canvas.GetLeft(TargetElement),
Canvas.GetTop(TargetElement));
}
else
{
var position = TargetElement.TranslatePoint(new Point(0, 0), (UIElement)TargetElement.Parent);
beginThickness = TargetLayer.GetParentLayoutInfo().Margin;
beginTargetThickness = TargetElement.Margin;
beginThickness.Left *= -1;
beginThickness.Top *= -1;
beginBound = new Rect(position, (Size)beginSize);
}
positionLimit = new Vector(
beginPosition.X + beginSize.X - TargetElement.GetDesignMinWidth(),
beginPosition.Y + beginSize.Y - TargetElement.GetDesignMinHeight());
base.OnDragStarted(horizontalOffset, verticalOffset);
}
private void UpdateInsertionAdorner(Point currentPosition, DependencyObject obj)
{
FrameworkElement listViewItem = Helpers.WPFVisualHelper.FindAncestor <ListBoxItem>(obj);
if (listViewItem != null)
{
if (_insertionAdorner == null)
{
_insertionAdorner = new InsertionAdorner(listViewItem);
AdornerLayer.Add(_insertionAdorner);
}
currentPosition = TargetElement.TranslatePoint(currentPosition, listViewItem);
double halfHeight = listViewItem.ActualHeight / 2;
_insertionAdorner.Position = (currentPosition.Y <= halfHeight) ?
InsertionAdorner.InsertionPosition.Top : InsertionAdorner.InsertionPosition.Bottom;
}
else
{
RemoveAdorners();
}
}
