navigation-routing

name	navigation-routing
description	Handles Prism region navigation, view routing, NavigationParameters, and navigation constants in the Desktop Boilerplate WPF/Prism repository. Invoke when adding navigation routes, managing region content, passing navigation parameters, or working with NavigationConstants.

Navigation Routing Skill

Overview

This skill covers the navigation system in Desktop Boilerplate, which uses Prism's region navigation pattern wrapped in a Contracts-layer INavigationService for decoupled view routing.

Core Components

INavigationService (Contracts Layer)

Defined in src/Vk.Dbp.Contracts/Services/INavigationService.cs, implemented by PrismNavigationService in src/Vk.Dbp.WpfWindow/Services/PrismNavigationService.cs.

public interface INavigationService
{
    void NavigateTo(string viewName, NavigationParameters parameters = null);
    void NavigateTo<TView>(NavigationParameters parameters = null);
    event Action<NavigationResult> NavigationCompleted;
}

PrismNavigationService wraps IRegionManager.RequestNavigate and always navigates to RegionNames.ContentRegion.

NavigationConstants

Defined in src/Vk.Dbp.WpfWindow/Constants/NavigationConstants.cs:

public static class RegionNames
{
    public const string ContentRegion = "ContentRegion";
}

public static class ViewNames
{
    public const string Dashboard = "Dashboard";
    public const string LoginView = "LoginView";
    public const string SelfCheck = "SelfCheck";
    public const string Production = "Production";
    // Add new view names here
}

public static class AccountActions
{
    public const string ChangePassword = "ChangePassword";
    public const string Logout = "Logout";
    public const string Shutdown = "Shutdown";
    public const string Close = "Close";
}

Navigation Patterns

Basic Navigation

// In ViewModel — use INavigationService, NOT IRegionManager
_navigationService.NavigateTo(ViewNames.Dashboard);

Navigation with Parameters

var parameters = new NavigationParameters
{
    { "UserId", userId },
    { "EditMode", true }
};
_navigationService.NavigateTo(ViewNames.UserManagement, parameters);

Receiving Parameters (INavigationAware)

public class DetailViewModel : BindableBase, INavigationAware
{
    public void OnNavigatedTo(NavigationContext navigationContext)
    {
        var userId = navigationContext.Parameters.GetValue<int>("UserId");
        var editMode = navigationContext.Parameters.GetValue<bool>("EditMode");
        // Initialize with parameters
    }

    public bool IsNavigationTarget(NavigationContext navigationContext) => true;

    public void OnNavigatedFrom(NavigationContext navigationContext) { }
}

Conditional Navigation (Login Check)

// In PrismBootstrapper.InitializeShell
var initialView = userSession.IsLoggedIn ? ViewNames.Dashboard : ViewNames.LoginView;
regionManager.RequestNavigate(RegionNames.ContentRegion, initialView);

Auto-Redirect on Navigation

public void OnNavigatedTo(NavigationContext navigationContext)
{
    if (_userSession.IsLoggedIn)
    {
        _navigationService.NavigateTo(ViewNames.Dashboard);
    }
}

View Registration

Views are registered in module RegisterTypes methods:

// In DbpAccountModule.RegisterTypes
containerRegistry.RegisterForNavigation<LoginView>();
containerRegistry.RegisterForNavigation<UserManagementView>();

// In DbpWorkshopModule.RegisterTypes
containerRegistry.RegisterForNavigation<Dashboard>();
containerRegistry.RegisterForNavigation<SelfCheck>();

Prism's ViewModelLocator automatically resolves ViewModels by convention (LoginView → LoginViewModel).

For non-convention mappings, register explicitly in PrismBootstrapper.ConfigureViewModelLocator:

ViewModelLocationProvider.Register<CustomView, CustomViewModel>();

Adding a New Navigation Route

1. Add view name constant to NavigationConstants.ViewNames.
2. Create the View (XAML) and ViewModel.
3. Register with RegisterForNavigation<TView>() in the module's RegisterTypes.
4. Add menu entry in HeaderViewModel with permission check via IMenuPermissionFilter.IsMenuVisible().
5. Navigate using _navigationService.NavigateTo(ViewNames.NewView).

Key Files

Component	Location
INavigationService	src/Vk.Dbp.Contracts/Services/INavigationService.cs
PrismNavigationService	src/Vk.Dbp.WpfWindow/Services/PrismNavigationService.cs
NavigationConstants	src/Vk.Dbp.WpfWindow/Constants/NavigationConstants.cs
PrismBootstrapper	src/Vk.Dbp.WpfWindow/PrismBootstrapper.cs
HeaderViewModel (menu navigation)	src/Vk.Dbp.WpfWindow/ViewModels/HeaderViewModel.cs

Common Issues

Issue: Navigation silently fails

Solution: Check that the view is registered with RegisterForNavigation<TView>() and the view name matches exactly (case-sensitive).

Issue: ViewModel not resolved

Solution: Ensure ViewModel naming follows Prism convention (XxxView → XxxViewModel) or add explicit mapping in ConfigureViewModelLocator.

Issue: Parameters lost after navigation

Solution: Ensure the target ViewModel implements INavigationAware and reads parameters in OnNavigatedTo, not in the constructor.

Issue: Using IRegionManager directly in ViewModels

Solution: Replace with INavigationService.NavigateTo() from Contracts layer. IRegionManager.RequestNavigate should only be used in PrismNavigationService and PrismBootstrapper.