How can I make the Silverlight ScrollViewer scroll to show a child control with focus?

Question

I have a ScrollViewer which contains a Grid with multiple controls in it. The user can tab through the controls, but eventually they tab to a control that isn\'t in view - so th

Answer 1

Just a slight enhancement. Still need to do this for Silverlight 4 by the way. Instead of GotFocus for each control you can handle the GotFocus of the scrollviewer itself and implement it just once.

 private void _ScrollViewer_GotFocus(object sender, RoutedEventArgs e)
        {
            FrameworkElement element = e.OriginalSource as FrameworkElement;

            if (element != null)
            {
                ScrollViewer scrollViewer = sender as ScrollViewer;
                scrollViewer.ScrollToVerticalOffset(GetVerticalOffset(element, scrollViewer));
            }

        }

        private double GetVerticalOffset(FrameworkElement child, ScrollViewer scrollViewer)
        {
            // Ensure the control is scrolled into view in the ScrollViewer. 
            GeneralTransform focusedVisualTransform = child.TransformToVisual(scrollViewer);
            Point topLeft = focusedVisualTransform.Transform(new Point(child.Margin.Left, child.Margin.Top));
            Rect rectangle = new Rect(topLeft, child.RenderSize);
            double newOffset = scrollViewer.VerticalOffset + (rectangle.Bottom - scrollViewer.ViewportHeight);
            return newOffset < 0 ? 0 : newOffset; // no use returning negative offset
        }