I used to be on a project that used Prism and when we needed a new service to do something, we'd just create an interface, a concrete class that implemented that interface and exported it, and then it just became available everywhere for [ImportingConstructor]. We didn't need to manually register it or anything. I no longer have access to that project, but I don't think there was any reflection magic that was done manually to accomplish this.

I'm in a new company and we are starting up a project using MEF / Prism and I'm trying to accomplish the same thing, but as of right now, I'm having to manually register items in order to import them. What am I missing?

I'm in .NET 4.8 WPF app

Additional info we are basing our project from this website

https://prismlibrary.com/index.html

This is our app class

   public partial class App
   {
      protected override Window CreateShell()
      {
         return Container.Resolve<ShellWindow>();
      }

      protected override void RegisterTypes(IContainerRegistry containerRegistry)
      {
         containerRegistry.RegisterSingleton<IStartupActionService, StartupActionService>();
         containerRegistry.RegisterSingleton<IGeneralNavigationService, GeneralNavigationService>();
         containerRegistry.RegisterSingleton<IExperimentSetupNavigationService, ExperimentSetupNavigationService>();
         containerRegistry.RegisterSingleton<IProtocolSetupNavigationService, ProtocolSetupNavigationService>();
         containerRegistry.RegisterSingleton<IOurProjectNavigationService, OurProjectNavigationService>();
         containerRegistry.RegisterSingleton<IOurProjectUiService, OurProjectUiService>();
         containerRegistry.RegisterManySingleton<WcfClientService>();
         containerRegistry.RegisterSingleton<IControlClientService, ControlClientService>();
      }
   }

Why do I have to register each new service? I've been reading about MEF, DryIoc, and others and I'm just not getting clear answers. Is there not a way to just have everything with an [Export] become immediately available for import?

Something else I need to do, that I think this whole registering thing is messing me up on is trying to come up with a way to have "dialogs" but tie them to a neutral class to make it more MVVM happy.

Dialog -> a region that pops open when you call a method. This method currently takes in a UserControl, assumed to have already been constructed and its ViewModel datacontext already attached.

What I would like to do and don't know how to start is

1. use a neutral container class to open one of these dialogs (similar to interaction request Notification
2. using attributes, attach an attribute to a view that indicates "I support this neutral container class" (assumed only one view per container)
3. this view supports [ImportingConstuctor] to bring in its ViewModel
4. the viewmodel itself supports [ImportingConstuctor] to bring in services needed
5. again, the desire to NOT need to register these items manually as we add them. Would like to add a service interface, the concrete class that [Export]s the interface and have it just available to the viewmodel and other services, and same for the views and viewmodels, export attribute tag them as necessary and have them just available to either/both grab an instance of them or manually create an instance of them and have their [ImportingConstructors] handled for me.