Which design pattern to use (i need something like mediator pattern)?

Question

I have a GUI application with a lot of controlles. The most part of them have events and controles are logically wired to each there. For example, i have 5 comboBoxes. If i choose something in cb1 and cb3 them cb2 must change a list of its available values. If i choose something in cb2 and ch4, them cb5 must load its list of its available values. All the articles i've found in the web says i should use mediator pattern in this case. But in all of these articles mediator - is something like a god class, which knows everything about all controlles and decides what should be done in case of some event. If i have 5-6 controlles - everything is ok. But what if i have something like 20 or 40 controlles? I guess mediator class will become a monster in this case. It'll be hard to do something with it (modify, or add new functionality).

Is there any other patterns, or good examples of mediator pathern, which will help to solve this situation?

PS: Sorry if there are already existing questions on this topic - there are so many questions with the same name, that it not so easy to find something i really need from all these topics.

Answer 1

Mediator is indeed the right choice here, however there is alternative option to use OBSERVER pattern which will allow you to keep logic separate. (cb2 observes cb1 and reacts approperly, cb3->cb2 etc).

With OBSERVER pattern you will have to link only 2 controls at a time, this is like chain.

Answer 2

Use the different actions as strategies Strategy Pattern and invoke a certain strategy from the Mediator, so that you would only need to change few lines of code if you need to add more controllers tomorrow.