windows phone 8 - How to set orientation of StackPanel dynamically? -

windows phone 8 - How to set orientation of StackPanel dynamically? -

i trying set orientation of stackpanel next giving me error, says orientation not have vertical definition. true way set orientation of stackpanel vertical dynamically?

stackpanel firstpanel = new stackpanel(); firstpanel.orientation = orientation.vertical;

did seek setting through xaml? or have @ this:

stackpanel orientation

windows-phone-8 orientation stackpanel