newDemoAvaloniaVal/AvaloniaValidation/MainWindow.axaml.cs

using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.IO;
using System.Linq;
using Avalonia.Controls;
using Avalonia.Interactivity;
using Avalonia.Media.Imaging;
using AvaloniaValidation.Models;

namespace AvaloniaValidation;

public partial class MainWindow : Window
{
    private ObservableCollection<EventPresenter> events = new ObservableCollection<EventPresenter>(); 

    public MainWindow()
    {
        InitializeComponent();
        
        using var context = new User1Context();
        var dataSourceEvent = context.Events.Select(it => new EventPresenter
        {
            Sobitie = it.Sobitie,
            Date = it.Date,
            Days = it.Days,
            City = it.City,
            Photo = it.Photo
        }).ToList();
    
        foreach (var eventItem in dataSourceEvent)
        {
            events.Add(eventItem);
        }
        EventListBox.ItemsSource = events;
    }
    
    public class EventPresenter : Event
    {
        public Bitmap? Image
        {
            get
            {
                try
                {
                        
                    string path = Path.Combine(AppContext.BaseDirectory, Photo);
    
                    if (File.Exists(path))
                    {
                        return new Bitmap(path); 
                    }
    
                    return null;
                }
                catch
                {
                    return null; 
                }
            }
        }
     }

    private void Registration(object? sender, RoutedEventArgs e)
    {
        new Registration().ShowDialog(this);
    }
}