Вам не нужно устанавливать Storyboard.Target
.
Просто напрямую анимируйте свойства объекта ScaleTransform в RenderTransform
:
<Storyboard>
<DoubleAnimation Storyboard.TargetProperty="RenderTransform.ScaleX"
From="0" To="1" Duration="0:0:2">
<DoubleAnimation.EasingFunction>
<BackEase/>
</DoubleAnimation.EasingFunction>
</DoubleAnimation>
<DoubleAnimation Storyboard.TargetProperty="RenderTransform.ScaleY"
From="0" To="1" Duration="0:0:2">
<DoubleAnimation.EasingFunction>
<BackEase/>
</DoubleAnimation.EasingFunction>
</DoubleAnimation>
</Storyboard>
В качестве альтернативы установите Storyboard.TargetName
:
<Storyboard>
<DoubleAnimation Storyboard.TargetName="MyRenderScaleTransform"
Storyboard.TargetProperty="ScaleX"
From="0" To="1" Duration="0:0:2">
<DoubleAnimation.EasingFunction>
<BackEase/>
</DoubleAnimation.EasingFunction>
</DoubleAnimation>
<DoubleAnimation Storyboard.TargetName="MyRenderScaleTransform"
Storyboard.TargetProperty="ScaleY"
From="0" To="1" Duration="0:0:2">
<DoubleAnimation.EasingFunction>
<BackEase/>
</DoubleAnimation.EasingFunction>
</DoubleAnimation>
</Storyboard>