private static void OnRequestBringIntoView(object sender, RequestBringIntoViewEventArgs e)
{
LoopPanel lp = sender as LoopPanel;
DependencyObject target = e.TargetObject as DependencyObject;
if (lp.BringChildrenIntoView && target != lp)
{
UIElement child = null;
while (target != null)
{
if ((target is UIElement) &&
lp.InternalChildren.Contains(target as UIElement))
{
child = target as UIElement;
break;
}
target = VisualTreeHelper.GetParent(target);
if (target == lp)
{
break;
}
}
if (child != null &&
lp.InternalChildren.Contains(child))
{
e.Handled = true;
// determine if the child needs to be brought into view
GeneralTransform childTransform = child.TransformToAncestor(lp);
Rect childRect = childTransform.TransformBounds(new Rect(new Point(0, 0), child.RenderSize));
Rect intersection = Rect.Intersect(new Rect(new Point(0, 0), lp.RenderSize), childRect);
// if the intersection is different than the child rect, it is either not visible
// or only partially visible, so adjust the Offset to bring it into view
if (!DoubleHelper.AreVirtuallyEqual(childRect, intersection))
{
if (!intersection.IsEmpty)
{
// the child is already partially visible, so just scroll it into view
lp.Scroll((lp.Orientation == Orientation.Horizontal)
? (DoubleHelper.AreVirtuallyEqual(childRect.X, intersection.X) ? childRect.Width - intersection.Width + Math.Min(0, lp.RenderSize.Width - childRect.Width) : childRect.X - intersection.X)
: (DoubleHelper.AreVirtuallyEqual(childRect.Y, intersection.Y) ? childRect.Height - intersection.Height + Math.Min(0, lp.RenderSize.Height - childRect.Height) : childRect.Y - intersection.Y));
}
else
{
// the child is not visible at all
lp.Scroll((lp.Orientation == Orientation.Horizontal)
? (DoubleHelper.StrictlyLessThan(childRect.Right, 0.0d) ? childRect.X : childRect.Right - lp.RenderSize.Width + Math.Min(0, lp.RenderSize.Width - childRect.Width))
: (DoubleHelper.StrictlyLessThan(childRect.Bottom, 0.0d) ? childRect.Y : childRect.Bottom - lp.RenderSize.Height + Math.Min(0, lp.RenderSize.Height - childRect.Height)));
}
}
}
}
}
public override void OnApplyTemplate()
{
LoopPanel = GetDescendantByType(this, typeof(LoopPanel)) as LoopPanel;
base.OnApplyTemplate();
}
public override void OnApplyTemplate()
{
LoopPanel = GetDescendantByType(this, typeof(LoopPanel)) as LoopPanel;
base.OnApplyTemplate();
}