PageService.cs

using System.Windows.Controls;
 
using CommunityToolkit.Mvvm.ComponentModel;
 
using Vereinsmeisterschaften.Contracts.Services;
using Vereinsmeisterschaften.ViewModels;
using Vereinsmeisterschaften.Views;
 
namespace Vereinsmeisterschaften.Services;

public class PageService : IPageService
{
    private readonly Dictionary<string, Type> _pages = new Dictionary<string, Type>();
    private readonly IServiceProvider _serviceProvider;

    public PageService(IServiceProvider serviceProvider)
    {
        _serviceProvider = serviceProvider;
        Configure<MainViewModel, MainPage>();
        Configure<WorkspaceViewModel, WorkspacePage>();
        Configure<CompetitionViewModel, CompetitionPage>();
        Configure<PeopleViewModel, PeoplePage>();
        Configure<PrepareRacesViewModel, PrepareRacesPage>();
        Configure<CreateDocumentsViewModel, CreateDocumentsPage>();
        Configure<TimeInputViewModel, TimeInputPage>();
        Configure<ResultsViewModel, ResultsPage>();
        Configure<AnalyticsViewModel, AnalyticsPage>();
        Configure<SettingsViewModel, SettingsPage>();
    }

    public Type GetPageType(string key)
    {
        Type pageType;
        lock (_pages)
        {
            if (!_pages.TryGetValue(key, out pageType))
            {
                throw new ArgumentException($"Page not found: {key}. Did you forget to call PageService.Configure?");
            }
        }
 
        return pageType;
    }

    public Page GetPage(string key)
    {
        var pageType = GetPageType(key);
        return _serviceProvider.GetService(pageType) as Page;
    }
 
    private void Configure<VM, V>()
        where VM : ObservableObject
        where V : Page
    {
        lock (_pages)
        {
            var key = typeof(VM).FullName;
            if (_pages.ContainsKey(key))
            {
                throw new ArgumentException($"The key {key} is already configured in PageService");
            }
 
            var type = typeof(V);
            if (_pages.Any(p => p.Value == type))
            {
                throw new ArgumentException($"This type is already configured with key {_pages.First(p => p.Value == type).Key}");
            }
 
            _pages.Add(key, type);
        }
    }
}