Good OOP Desing in WinForm App

Question

didn't think this fit into the other discussion boards so I thought this would be the most acceptable place to post these questions... I’m in the process of building a Windows app with C# and I’m cannot seem to find any detailed information on “good” OOP design… honestly. Basically, I’m having trouble determining how certain classes and forms “should” be designed. For example: 1. I assume I should separate the logic from the UI. I have a number of forms that have comboboxes that contain generic information such as a list of states or sales person names. What is the “best” way to do this, do I create a class, incorporate it in the form, etc… 2. The program is an order entry app so I have a one-to-many relationship between the order information and the items ordered. I thought about creating two classes one for the order and one for the item ordered. I assume I would have to create a collection of the items ordered class to populate the UI. Is this approach sound? Is there a standard way of creating these classes? Any help, examples, book ideas would be greatly appreciated. Regards, Andrew