WPF: Showing and hiding items in an ItemsControl with effects

Question

I\'ve been using this great article as a basis for showing and hiding elements with a transition effect. It works very neatly in that it lets you bind the Visibility

Answer 1

@Fredrik Hedblad Nicely done. I do have a few remarks.

• When adding an item the animation sometimes starts on the previously added item.

• Inserting items into the list, added them all to the bottom (so no sorted list support)

• (personal issue: needed separate animation for each item)

In code below in have an addapted version, which resolves the issues listed above.

public class ItemsSourceBehavior
{
    public static void SetItemsSource(DependencyObject element, IList value)
    {
        element.SetValue(ItemsSourceProperty, value);
    }

    public static IList GetItemsSource(DependencyObject element)
    {
        return (IList) element.GetValue(ItemsSourceProperty);
    }

    private static void ItemsSourcePropertyChanged(DependencyObject source, DependencyPropertyChangedEventArgs e)
    {
        //If animations need to be run together set this to 'false'.
        const bool separateAnimations = true;

        var itemsControl = source as ItemsControl;
        var itemsSource = e.NewValue as IList;
        if (itemsControl == null)
        {
            return;
        }
        if (itemsSource == null)
        {
            itemsControl.ItemsSource = null;
            return;
        }

        var itemsSourceType = itemsSource.GetType();
        var listType = typeof (ObservableCollection<>).MakeGenericType(itemsSourceType.GetGenericArguments()[0]);
        var mirrorItemsSource = (IList) Activator.CreateInstance(listType);
        itemsControl.SetBinding(ItemsControl.ItemsSourceProperty, new Binding {Source = mirrorItemsSource});

        foreach (var item in itemsSource)
        {
            mirrorItemsSource.Add(item);
            if (separateAnimations)
                StartFadeInAnimation(itemsControl, new List