private void InitializeCompositionObjects()
{
_headersScrollingProperties = HeadersPanelHost.ScrollProperties();
_contentScrollingProperties = ScrollViewer.ScrollProperties();
_compositor = _headersScrollingProperties.Compositor;
_selectedHeaderIndicatorVisual = _selectedHeaderIndicator.Visual();
_selectedHeaderIndicatorHostVisual = _selectedHeaderIndicatorHost.Visual();
}
private void OnLoaded(object sender, RoutedEventArgs e)
{
Loaded -= OnLoaded;
if (Items == null)
{
return;
}
SetSelectedHeaderIndicatorVisualBoundaries();
for (var i = 0; i < Items.Count; i++)
{
var tabItem = ContainerFromIndex(i) as TabItem;
if (tabItem == null)
{
continue;
}
var header = new TabHeaderItem
{
DataContext = Items[i],
Content = tabItem.Header,
HeaderIconStyle = tabItem.HeaderIconStyle,
ContentTemplate = HeaderTemplate,
IsChecked = i == 0
};
// Have to do this to avoid a bug where RadioButton's GroupName
// doesn't function properly after Reloaded.
header.Loaded += async(s, args) =>
{
// TODO: There should be a better way to handle this, at system level??
// Put a short delay here to allow the system to calculate the Offset
// before we can animate it.
await Task.Delay(1000);
_isLoaded = true;
var h = (TabHeaderItem)s;
h.GroupName = "Headers";
UpdateHeaderVisuals();
SyncSelectedHeaderIndicatorVisual();
};
header.Unloaded += (s, args) =>
{
var h = (TabHeaderItem)s;
h.GroupName = string.Empty;
};
header.Checked += async(s, args) =>
{
UpdateHeaderVisuals();
var h = (TabHeaderItem)s;
SelectedIndex = GetHeaderIndex(h);
// TODO: We might be able to monitor the scrolling on the HeadersPanelHost and sync the selection visual with the scrolling in real time.
// OnHeadersPanelHostDirectManipulationStarted(null, null);
await HeadersPanelHost.ScrollToElementAsync(header, false, bringToTopOrLeft : false);
SyncSelectedHeaderIndicatorVisual();
};
header.Unchecked += (s, args) =>
{
UpdateHeaderVisuals();
};
header.SizeChanged += (s, args) =>
{
if (!_isLoaded)
{
return;
}
UpdateHeaderVisuals();
SyncSelectedHeaderIndicatorVisual();
};
Headers.Add(header);
}
}
