AvaloniaKnuScool/ViewModels/MainWindowViewModel.cs

using Avalonia.Controls;
using AvaloniaApplication1.Models;
using ReactiveUI;
using System.Linq;
using System.Net;

namespace AvaloniaApplication1.ViewModels
{
    public class MainWindowViewModel : ViewModelBase
    {
        public static ScoolContext DB = new ScoolContext();

        UserControl us = new Authorization();

        public UserControl US
        {
            get => us;
            set => this.RaiseAndSetIfChanged(ref us, value);
        }

        AuthorizationViewModel authorizationvm = new AuthorizationViewModel();
        PersonalPageViewModel personalpagevm;
        CoursesListViewModel coursesvm = new CoursesListViewModel();

        public AuthorizationViewModel AuthorizationVM
        {
            get => authorizationvm;
            set => authorizationvm = value;
        }

        public PersonalPageViewModel PPVM
        {
            get => personalpagevm;
            set => personalpagevm = value;
        }

        public CoursesListViewModel CourseVM
        {
            get => coursesvm;
            set => coursesvm = value;
        }

        public void GoAuth()
        {
            int index = AuthorizationVM.Auth();
            if (index != 0)
            {
                if(DB.Users.Where(x=>x.IdUser == index).Select(x=>x.IdRole).FirstOrDefault()==2)
                {
                    PPVM = new PersonalPageViewModel(index);
                    US = new PersonalPage();
                }
                else
                {
                    US = new CoursesList();
                }
            }
        }
    }
}