Issues with Measure/Arrange in custom Control With FlipView

Question

Hi all,

I'm having some issues with Measure/Arrange in my custom control. My control uses a FlipView, which in turns contains some ScrollViewers, that in turn contain content.

I want the control to take up as much space as is available at any time.

I tried to override MeasureOverride and ArrangeOverride, but can't seem to get it right. The elements inside the FlipView always end up with a size of 0.

I created a small simplified sample problem to work on the core of the problem. It looks as following:

    class CustomControl : ContentControl
    {
        private List<Canvas> _ChildCanvases;
        private FlipView _ChildFlipView;
        private List<ScrollViewer> _ChildScrollViewers;

        public CustomControl()
        {
            this.HorizontalAlignment = Windows.UI.Xaml.HorizontalAlignment.Stretch;
            this.VerticalAlignment = Windows.UI.Xaml.VerticalAlignment.Stretch;

            _ChildFlipView = new FlipView();
            _ChildFlipView.HorizontalAlignment = Windows.UI.Xaml.HorizontalAlignment.Stretch;
            _ChildFlipView.VerticalAlignment = Windows.UI.Xaml.VerticalAlignment.Stretch;
            _ChildFlipView.Background = new SolidColorBrush(Colors.Olive);

            this.Content = _ChildFlipView;
            _ChildScrollViewers = new List<ScrollViewer>();
            _ChildCanvases = new List<Canvas>();

            for (int i = 0; i < 3; i++)
            {
                ScrollViewer sv = new ScrollViewer();
                _ChildScrollViewers.Add(sv);
                _ChildFlipView.Items.Add(sv);

                Canvas c = new Canvas();
                _ChildCanvases.Add(c);

                c.Background = new Windows.UI.Xaml.Media.SolidColorBrush(Windows.UI.Colors.Red);
                c.Width = 4000;
                c.Height = 8000;

                sv.Content = c;
                //sv.Width = 1000;
                //sv.Height = 1000;
            }
        }

        protected override Windows.Foundation.Size MeasureOverride(Size availableSize)
        {
            Size size = new Size(availableSize.Width, availableSize.Height);
            _ChildFlipView.Measure(new Size(availableSize.Width, availableSize.Height));
            return size;
        }

        protected override Windows.Foundation.Size ArrangeOverride(Size finalSize)
        {
            _ChildFlipView.Arrange(new Rect(0, 0, finalSize.Width, finalSize.Height));

            return new Size(finalSize.Width, finalSize.Height);
        }
    }

I want to stick this control inside, say a Grid. The problem is, that once the control is laid out, the ScrollViewer's are all of width and height 0.

Any idea why this might be?

Thanks,

Tomas