PrismDelayedScopedRegionCreationBehavior

Allows to create scoped regions

Initialization

Register DelayedScopedRegionCreationBehavior in Container

...ServiceLocator will return this behavior for DelayedRegionCreationBehavior

Register ShellService if we want to show multiple shells

protected override void RegisterRequiredTypes(IContainerRegistry containerRegistry)
{
    // DelayedScopedRegionCreationBehavior
    containerRegistry.Register<DelayedRegionCreationBehavior, DelayedScopedRegionCreationBehavior>();
    
    // Shell Service
    containerRegistry.RegisterSingleton<IShellService, ShellService>();

    base.RegisterRequiredTypes(containerRegistry);
}

Add RegionManagerAwareBehavior (RegionBehavior) to resolve IRegionManagerAware for Views

protected override void ConfigureDefaultRegionBehaviors(IRegionBehaviorFactory regionBehaviors)
{
    base.ConfigureDefaultRegionBehaviors(regionBehaviors);
   
    regionBehaviors.AddIfMissing(RegionManagerAwareBehavior.BehaviorKey, typeof(RegionManagerAwareBehavior));
}

Show New Shell

Inject the service and use it to show new shell

public class MainWindowViewModel
{
    private IShellService shellService;
    private DelegateCommand showShellCommand;

    public MainWindowViewModel(IShellService shellService)
    {
        if (shellService is null)
            throw new ArgumentNullException(nameof(shellService));

        this.shellService = shellService;
    }

    public DelegateCommand ShowShellCommand
    {
        get
        {
            if (showShellCommand == null)
                showShellCommand = new DelegateCommand(ExecuteShowShellCommand);
            return showShellCommand;
        }
    }

    private void ExecuteShowShellCommand()
    {
        shellService.ShowShell<MainWindow>();
    }
}

IRegionManagerAware

To get the RegionManager for the region scope

public class MainWindowViewModel : IRegionManagerAware
{
    public IRegionManager RegionManager { get; set; }
}

Resources:

• Prism Library
• Prism Problems & Solutions: Showing Multiple Shells