Hello there,

I am trying to design an MVVM app and failing :|

When I started out writing it, I more or less had 4 layers.

Model, Service, ViewModel and view.

My current sticking point is, what excactly is a service? From the googling I have done so far, I don't think there is a consensus. Some people say that a Service class should be stateless. Which is fine. But, if so, where do I put all my classes that need a state?

I have a read a few posts on stackoverflow that suggest an intermediate layer might be something like DomainLogic, or BusinessLogic..

Should I even care about making the distinction? Should I just jam it all in and call it a service layer?

I know it all depends on the application (it is a trading app), but I would be interested in hearing thoughts on what people think.

Thank you kindly