Shaker/Avalonia/ShakerApp/ViewModels/MainPage/MainPageViewModel.cs

using Avalonia.Collections;
using Shaker.Model;
using Shaker.Models;
using ShakerApp.Views;
using System;
using System.Collections.Generic;
using System.Diagnostics.CodeAnalysis;
using System.Linq;
using System.Reflection;
using System.Text;
using System.Threading.Tasks;

namespace ShakerApp.ViewModels
{
    internal class MainPageViewModel:ViewModelBase<IModel>
    {
        private MainPageType mainPageType = Shaker.Models.MainPageType.StartPage;

        public AvaloniaList<MainPageItemViewModel> MainPages { get; } = new AvaloniaList<MainPageItemViewModel>();
        private IReadOnlyList<IMainPageViewModel> MainPageViewModels { get; } = new List<IMainPageViewModel>()
        {
            StartPageViewModel.Instance,
            SineMainPageViewModel.Instance,
            RandomMainPageViewModel.Instance,
            OutSignalMainPageViewModel.Instance,
        };
        private MainPageViewModel()
        {
            this.GetType().Assembly.GetTypes()
                .Where(x => x.GetCustomAttribute<MainPageAttribute>() != null && x.IsAssignableTo(typeof(Views.IMainPage)) && x.IsAnsiClass && !x.IsAbstract)
                .ToList()
                .ForEach(x =>
                {
                    var page = x.GetCustomAttribute<MainPageAttribute>();
                    if (page == null) return;
                    MainPages.Add(new MainPageItemViewModel(page.PageType,x)
                    {
                        Cache = page.Cache,
                    });
                });
            if(MainPages.Count==0)
            {
                Environment.Exit(0);
                return;
            }
            MainPageType = MainPageType.StartPage;
        }
        static MainPageViewModel()
        {

        }
        public MainPageType MainPageType 
        {
            get => mainPageType;
            set
            {
                SetProperty(ref mainPageType, value);
                Content = MainPages.First(x => x.PageType == value).Content;
                MainPage = MainPageViewModels.First(x => x.PageType == value);
            }
        }
        [AllowNull]
        public IMainPageViewModel MainPage { get; private set; }
        public static MainPageViewModel Instance { get; } = new MainPageViewModel();
    }
}