Pfthb

I'm using Prism 7.1 WPF and Prism Unity.

Before the main <prism:PrismApplication/> runs, or when the main Prism window appears, I want to have a modal pop-up window for user to input some data.
The input data would be for user login, and, more importantly, to determine which Prism modules to load into the application.

How would I go about doing this? I have tried to display a custom WPF window in the following PrismApplication overload methods, but either the window doesn't appear, or the entire application closes:

public partial class App : PrismApplication

 protected override void OnStartup(StartupEventArgs e)
 
 base.OnStartup(e);
 

 protected override IModuleCatalog CreateModuleCatalog()
 
 return base.CreateModuleCatalog();
 

 protected override void RegisterTypes(IContainerRegistry containerRegistry)
 
 

 protected override Window CreateShell()
 
 return ServiceLocator.Current.GetInstance<MainWindow>();
 

 protected override void OnInitialized()
 
 base.OnInitialized();
 

For example, if I put in a call to display a custom WPF window in the CreateModuleCatalog(), it will show, however the entire application closes:

 protected override IModuleCatalog CreateModuleCatalog()
 
 LoginWindow loginWindow = new LoginWindow();
 if (loginWindow.ShowDialog() == true)
 
 // OK
 
 else
 
 // Cancel
 

 return base.CreateModuleCatalog();
 

... and if I put the call in OnStartup(), it won't show until all the other overrides are executed and the main Prism window is displayed (which is too late to process the user's input):

 protected override void OnStartup(StartupEventArgs e)
 
 base.OnStartup(e);

 LoginWindow loginWindow = new LoginWindow();
 if (loginWindow.ShowDialog() == true)
 
 // OK
 
 else
 
 // Cancel
 
 

I've played around with the different methods, changed the position of the calls to the base class's method etc, but can't seem to get it working. Can anyone suggest how this can be done?
The reason for this is that I don't want to load entire modules into the application if I don't need to (based upon the user input).
Thanks....