Catrobat.IDE.WindowsPhone.Controls.SoundControls.SoundPlayButton.GroupChanged C# (CSharp) Method

        private static void GroupChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            var oldGroup = e.OldValue as SoundPlayButtonGroup;
            var newGroup = e.NewValue as SoundPlayButtonGroup;

            if (oldGroup != null)
                oldGroup.UnRegister(d as SoundPlayButton);

            if (newGroup != null)
                newGroup.Register(d as SoundPlayButton);
        }