Rect2 Rect2 MainCanvas. :
Canvas.SetTop(Rect2, Canvas.GetTop(Rect2) + Canvas.GetTop(ChildCanvas2));
:
private void btn2_Click(object sender, RoutedEventArgs e)
{
GeneralTransform transform = Rect2.TransformToVisual(MainCanvas);
Rect rect = transform.TransformBounds(new Rect(0, 0, Rect2.Width, Rect2.Height));
ChildCanvas2.Children.Remove(Rect2);
MainCanvas.Children.Remove(ChildCanvas2);
Canvas.SetLeft(Rect2, rect.Left);
Canvas.SetTop(Rect2, Canvas.GetTop(Rect2) + Canvas.GetTop(ChildCanvas2));
MainCanvas.Children.Add(Rect2);
}
Rect2.TransformToVisual transform.TransformBounds , . :
ChildCanvas2.Children.Remove(Rect2);
MainCanvas.Children.Remove(ChildCanvas2);
Canvas.SetLeft(Rect2, Canvas.GetLeft(Rect2) + Canvas.GetLeft(ChildCanvas2));
Canvas.SetTop(Rect2, Canvas.GetTop(Rect2) + Canvas.GetTop(ChildCanvas2));
MainCanvas.Children.Add(Rect2);
EDIT: :
ChildCanvas2.Children.Remove(Rect2);
MainCanvas.Children.Remove(ChildCanvas2);
Canvas.SetLeft(Rect2, Canvas.GetLeft(Rect2) + Canvas.GetLeft(ChildCanvas2));
Canvas.SetTop(Rect2, Canvas.GetTop(Rect2) + Canvas.GetTop(ChildCanvas2));
Canvas.SetRight(Rect2, Canvas.GetRight(Rect2) + Canvas.GetRight(ChildCanvas2));
Canvas.SetBottom(Rect2, Canvas.GetBottom(Rect2) + Canvas.GetBottom(ChildCanvas2));
MainCanvas.Children.Add(Rect2);