Animating UserControl - wpf

Question

I've made an opacity animation using Blend on one my two UserControls, deleted <UserControl.Resources>, <UserControl.Triggers> and Storyboard.TargetName from that, placed it in App.xaml and it looks like:
<Storyboard x:Key="Loaded">
<DoubleAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.Opacity)" >
<EasingDoubleKeyFrame KeyTime="0" Value="0"/>
<EasingDoubleKeyFrame KeyTime="0:0:3" Value="1"/>
</DoubleAnimationUsingKeyFrames>
</Storyboard>
when I call it in code like this before setting the Content of my ContentControl:
Storyboard sb = FindResource("Loaded") as Storyboard;
sb.begin(uc1);
content.Content = uc1;
//and
Storyboard sb = FindResource("Loaded") as Storyboard;
sb.begin(uc2);
content.Content = uc2;
it works as expected. For the transform animation, I've deleted the TransformGroup as well in addition to those above and now it looks like:
<Storyboard x:Key="Unloaded">
<DoubleAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.RenderTransform).(TransformGroup.Children)[3].(TranslateTransform.X)">
<EasingDoubleKeyFrame KeyTime="0" Value="0"/>
<EasingDoubleKeyFrame KeyTime="0:0:3" Value="-800"/>
</DoubleAnimationUsingKeyFrames>
</Storyboard>
If I call it in the same way, I get this error:
System.InvalidOperationException: ''[Unknown]' property does not point to a DependencyObject in path '(0).(1)[3].(2)'.'
How to fix the problem?

Answer 1

You will need to add a RenderTransform to your UserControl which is similar to the Storyboard.TargetProperty which currently expects a TransformGroup with 4th child as TranslateTransform.
Add the below code to each of your two UserControls:
<UserControl x:Class="YourUserControl"
...>
<UserControl.RenderTransform>
<TransformGroup>
<RotateTransform/>
<ScaleTransform/>
<SkewTransform/>
<TranslateTransform/>
</TransformGroup>
</UserControl.RenderTransform>