New Post: Cascading dropdowns in custom DynamicTypeForms

I am trying to create a form definition in the admin console that will allow cascading dropdown behavior for two dropdowns. For example: VehicleMake dropdown will scope or filter data in a VehicleSeries dropdown dynamically when a user selects a make.

Is there a way I can leverage the current binding engine and a StaticMethodCall to make this happen dynamically or do I need to create a custom user control that injects some javascript or alternate binding functionality to make this happen?

Thanks.