Can You Use A DynamicResource in a Storyboard Contained Within Style Or ControlTemplate

Question

I am trying to use a DynamicResource in Storyboard contained within a ControlTemplate.

But, when I try to do this, I get a 'Cannot freeze this Storyboard timeline tree for use across threads' error.

What is going on here?

Answer 1

In some scenarios, there is a workaround:

• introduce an attached property,
• specify a style trigger for that introduced property with desired setter(s)

Answer 2

No, you can't use a DynamicResource in a Storyboard that is contained within a Style or ControlTemplate. In fact, you can't use a data binding expression either.

The story here is that everything within a Style or ControlTemplate must be safe for use across threads and the timing system actually tries to freeze the Style or ControlTemplate to make them thread-safe. However, if a DynamicResource or data binding expression is present, it is unable to freeze them.

For more info see: MSDN Link. Check out the 'Animate in a Style' and the 'Animate in a ControlTemplate' sections (this documentation page is rather long).

And for a workaround (at least for my scenario) see: WPF Forum Post.

Hope this helps someone. I've lost more than enough hair on it.

Cory