/// <summary>
/// Each time a property change, we have to reposition
/// </summary>
private static void OnCarouselPropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
Carousel carouselControl = (Carousel)d;
if (e.Property == SelectedIndexProperty)
{
var newValue = (int)e.NewValue == -1 ? null : carouselControl.Items[(int)e.NewValue];
var oldValue = e.OldValue == null ? null : carouselControl.Items.ElementAtOrDefault((int)e.OldValue);
if (oldValue != null)
{
var item = (CarouselItem)carouselControl.ContainerFromIndex((int)e.OldValue);
if (item != null)
{
item.IsSelected = false;
}
}
bool isNewSelectedItem = carouselControl.SelectedItem != newValue;
if (newValue != null)
{
var item = (CarouselItem)carouselControl.ContainerFromIndex((int)e.NewValue);
if (item != null)
{
item.IsSelected = true;
}
carouselControl.FocusContainerFromIndex((int)e.NewValue);
}
// double check
if (isNewSelectedItem)
{
carouselControl.SetValue(SelectedItemProperty, newValue);
var newValues = new List <object>()
{
newValue
};
var oldValues = oldValue == null ? new List <object>() : new List <object>()
{
oldValue
};
var args = new SelectionChangedEventArgs(oldValues, newValues);
carouselControl.SelectionChanged?.Invoke(carouselControl, args);
return;
}
}
else if (e.Property == SelectedItemProperty)
{
var index = e.NewValue == null ? -1 : carouselControl.Items.IndexOf(e.NewValue);
// double check
if (carouselControl.SelectedIndex != index)
{
carouselControl.SetValue(SelectedIndexProperty, index);
var newValues = new List <object>()
{
e.NewValue
};
var oldValues = e.OldValue == null ? new List <object>() : new List <object>()
{
e.OldValue
};
var args = new SelectionChangedEventArgs(oldValues, newValues);
carouselControl.SelectionChanged?.Invoke(carouselControl, args);
return;
}
}
carouselControl.UpdatePositions();
}