Let’s say I have a view that must open another window on command. Where would this code sit?<\/p>\n
The model? Don’t be ridiculous.<\/p>\n
The view model? Yes, it’s where the command handlers are, but view model is not supposed to know about the views, and this would not be testable.<\/p>\n
The View? Well, maybe, but aren’t the command handlers in view model? Besides, the view may not have enough data to create the desired window.<\/p>\n
I realized, that all WPF apps that I created so far had pretty much static UI defined at startup, and any simple dialogs that needed to be shown dynamically were created by a “dialog service”.<\/p>\n
Surprisingly, quick googling gives very little insight on the topic, although it comes with with this answer<\/a> and this article<\/a>.<\/p>\n They seem to advise to create the views in a special layer (“controller”), talking to it via a service locator or an event broker. This kind of makes sense, because none of the 3 components of MVVM is well equipped for making new views. On the other hand, it is annoying, since it means one more moving part.<\/p>\n","protected":false},"excerpt":{"rendered":"