I'm not sure any of the answers above have been that helpful.
I have written similar components using expression trees. You can build lambda expressions that represent predicates, compile and execute them, all dynamically, and then trigger some action in response. This approach is powerful, flexible and strips out all the if/else horror (which is definitely not the way to go).
However, what you are really talking about is logic programming. There are numerous implementations of Prolog over .NET. Prolog is a logic based language, used alot for AI applications, that starts to become seriously powerful once you have your head around its paradigm.
Have a look at some of these ..