GazpromApp/Views/MainWindow.axaml.cs

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Threading.Tasks;
using Avalonia.Controls;
using Avalonia.Interactivity;
using Avalonia.Platform.Storage;
using CommunityToolkit.Mvvm.Messaging;
using GazpromApp.Messages;
using GazpromApp.ViewModels;

namespace GazpromApp.Views;

public partial class MainWindow : Window
{
    private bool _canClose = false;
    public MainWindow()
    {
        InitializeComponent();

        if (Design.IsDesignMode)
            return;
            
        WeakReferenceMessenger.Default.Register<MainWindow, RequestImageMessage>(this, HandleImageSelection);
        WeakReferenceMessenger.Default.Register<MainWindow, ViewImageMessage>(this, HandleImageViewer);
        WeakReferenceMessenger.Default.Register<MainWindow, ErrorMessage>(this, HandleErrorViewer);
        WeakReferenceMessenger.Default.Register<MainWindow, SaveChangesResult>(this, HandleSave);
    }
    
    private static void HandleImageSelection(MainWindow sender, RequestImageMessage msg)
    {
        var files = sender.StorageProvider.OpenFilePickerAsync(new FilePickerOpenOptions
        {
            AllowMultiple = true,
            Title = "Выберите одну или несколько картинок",
            FileTypeFilter = [FilePickerFileTypes.ImageAll]
        });
    
        msg.Reply(files);
    }

    private static void HandleImageViewer(MainWindow sender, ViewImageMessage msg)
    {
        var dialog = new ImageView
        {
            DataContext = msg.Image
        };
        msg.Reply(dialog.ShowDialog<ImageViewModel?>(sender));
    }

    private static void HandleErrorViewer(MainWindow sender, ErrorMessage msg)
    {
        var dialog = new ErrorView
        {
            DataContext = msg.Error
        };
        msg.Reply(dialog.ShowDialog<ErrorViewModel?>(sender));
    }
    
    private void TreeView_OnSelectionChanged(object? sender, SelectionChangedEventArgs e)
    {
        if (e.AddedItems.Count > 0)
            WeakReferenceMessenger.Default.Send(new SelectionChangedMessage((ViewModelBase)e.AddedItems[0]!));
    }

    private void HandleSave(object sender, SaveChangesResult msg)
    {
        if (msg.Cancel) return;
        if (msg.Save)
            ((MainWindowViewModel)DataContext!).SyncDbCommand.Execute(null);
        ForceClose();
    }

    private void ForceClose()
    {
        _canClose = true;
        Close();
    }
    
    private void Window_OnClosing(object? sender, WindowClosingEventArgs e)
    {
        if (_canClose) return;
        if (!((MainWindowViewModel)DataContext!).CanSync) return;
        var dialog = new SaveChangesView
        {
            DataContext = new SaveChangesViewModel()
        };
        dialog.ShowDialog<SaveChangesViewModel?>(this);
        e.Cancel = true;
    }
}