Animating Custom Attached Properties in SL2
One feature in SL2 that was added between Beta 2 and RTW is a new constructor to the PropertyPath class that can be used from code. You can now do the following from code:
Storyboard.SetTargetProperty(myAnimation, new PropertyPath(MyCustomClass.MyCustomDP));
This is especially important if you are trying to target an animation at a custom attached property. For example:
<DoubleAnimation Storyboard.TargetProperty="(custom:MyCustomClass.MyCustomAttachedDP)" .../>
Specifying these types of property path from a string representation
presents a number of complications on the SL, and is not currently
supported. This piece of XAML currently raises an
InvalidOperationException with message "Cannot
resolve TargetProperty (custom:MyCustomClass.MyCustomAttachedDP)".
Please note that this only applies to custom attached properties - attached properties of built-in objects (e.g., Canvas.Top) as well as custom non-attached properties should work just fine. As reference, an overview of the PropertyPath syntax can be found here.
Hopefully this will unblock you if you run into this limitation!
Ed
