I have a model where 1 object, say "Car", has an association to a list of sub-objects "Parts", say a wheel, a seat and an engine. These sub-objects have a 1-1 relation with my next object Buyer, who wants 1 piece of every car. How would I get this into a form, using 1 dropdown per Car. Edit: For each Car the Buyer can select 1 Part of that specific Car. These Parts are all unique to each Car, say a "Ferrari F430 exhaust pipe" that only matches to the "Ferrari F430" Car object. For the Buyer, I then want to get one place where he/she can pick 1 Part for each Car available.
Robert van 't Hof
You can use the template grid combined with the reference selector to realize this functionallity. I'm not sure if I completely understand you, but I think you have to do the following:
Add a template grid widget in your form, and connect the (according to your model description) car metaobject. Use in the template grid widget the reference selector widget for selecting a part for each car.
If this is not an answer to your question, please upload a screenshot of your metamodel.