We’ve seen how the Windows 10 AdaptiveTrigger can help you create a dynamic responsive UI based on the height or width of the device or screen. However, this trigger is limited to a specific value for each dimension, and offers no way to respond to changes in the relationship between them, such as to determine the orientation or aspect ratio of the app.
Fortunately, you are not limited to only the AdaptiveTrigger in Windows 10; you can create your own custom statetriggers based on virtually any property, even those not at all related to the UI. In this post, we’ll look at how we combined both the width and orientation properties of the app to create a custom OrientationSize trigger to switch between visual states using these properties.
Read more at the Falafel Software Blog: Windows 10 Development: Custom StateTriggers