FrameworkPropertyMetadataOptions.AffectsParentArrange in Avalonia UI?

Question

When declaring a property in WPF, you can set metadata like this

public static readonly DependencyProperty IsStopVisibleProperty = 
    DependencyProperty.Register("IsStopVisible", typeof(bool), typeof(MediaPlayer),
    new FrameworkPropertyMetadata(true, FrameworkPropertyMetadataOptions.AffectsParentArrange));

In Avalonia UI, there is no parameter to set metadata

public static readonly StyledProperty<bool> IsStopVisibleProperty = 
    AvaloniaProperty.Register<MediaPlayer, bool>(nameof(IsStopVisible), true);

What's the equivalent of FrameworkPropertyMetadataOptions.AffectsParentArrange ?

Answer 1

The simplest way to make a property affect the arrange of the control itself is to add a call to AffectsArrange in your control's static constructor:

static MediaPlayer()
{
    AffectsArrange(IsStopVisibleProperty);
}

However this is the equivalent of WPF's FrameworkPropertyMetadataOptions.AffectsArrange flag, not AffectsParentArrange . It is quite unusual for a control's property to directly affect the parent control's arrange - the scenario for AffectsParentArrange is usually limited to attached properties on Panel controls. Because of this, Avalonia's AffectsParentArrange is a protected method on Panel so will probably be unavailable in your control.

However if you're sure that you need to invalidate the parent's arrange on property change, probably the best way to do this would be to simply invalidate the parent arrange in OnPropertyChanged :

        protected override void OnPropertyChanged<T>(AvaloniaPropertyChangedEventArgs<T> change)
        {
            if (change.Property == IsStopVisibleProperty)
            {
                ((Control)Parent)?.InvalidateArrange();
            }

            base.OnPropertyChanged(change);
        }