We cannot change the value of a DependencyProperty which has been animated

[dr1rrb]

I'm submitting a...

• Bug report (I searched for similar issues and did not find one)

Current behavior

Once an animation has been used to alter a DependencyProperty, we cannot change its value using the property accessor.

Expected behavior

During the animation, the SetValue(DP, value) has no effect (but the value is stored for future animations), and once the animation is completed, we can change the value using SetValue(DP, value), and future animations use this new value as initial value.

Minimal reproduction of the problem with instructions

1. Alter a property using an animation

var animation = new DoubleAnimation
{
	To = 50,
	Duration = new Duration(TimeSpan.FromSeconds(10))
};
Storyboard.SetTargetProperty(animation, nameof(TranslateTransform.Y));
Storyboard.SetTarget(animation, _transform);

new Storyboard
{
	Children = { animation}
}.Begin();

2. Alter the property using SetValue:

_transform.Y = 0; // This won't have any effect
Assert.IsTrue(_transform.Y == 50); // This will pass 😱

Workaround

You cant alter the value using another animation.

Environment

Nuget Package: Uno.UI
Package Version(s): irrelevant
Affected platform(s):

• iOS
• Android
• WebAssembly
• Windows
• Build tasks

Visual Studio: irrelevant
Relevant plugins: none

[jeanplevesque]

I have the same problem.
This is my workaround:

_transform.Y = y; // Just this doesn't work.
#if __IOS__ || __ANDROID__
_transform.SetValue(TranslateTransform.YProperty, y, DependencyPropertyValuePrecedences.Animations);
#endif

[MatFillion]

@dr1rrb