auto_service/AutoService/App.axaml.cs

using AutoService.ViewModels;
using Avalonia;
using Avalonia.Controls.ApplicationLifetimes;
using Avalonia.Data.Core.Plugins;
using Avalonia.Markup.Xaml;
using Microsoft.Extensions.DependencyInjection;
using System;
using System.Linq;

namespace AutoService
{
    public partial class App : Application
    {
        private readonly IServiceProvider _provider;

        public App(IServiceProvider provider)
        {
            _provider = provider;
        }
        public override void Initialize()
        {
            AvaloniaXamlLoader.Load(this);
        }

        public override void OnFrameworkInitializationCompleted()
        {
            if (ApplicationLifetime is IClassicDesktopStyleApplicationLifetime desktop)
            {
                // Avoid duplicate validations from both Avalonia and the CommunityToolkit. 
                // More info: https://docs.avaloniaui.net/docs/guides/development-guides/data-validation#manage-validationplugins
                DisableAvaloniaDataAnnotationValidation();

                var win = _provider.GetRequiredService<MainWindow>();
                var vm = _provider.GetRequiredService<MainWindowVM>();
                win.DataContext = vm;
                desktop.MainWindow = win;
            }

            base.OnFrameworkInitializationCompleted();
        }

        private void DisableAvaloniaDataAnnotationValidation()
        {
            // Get an array of plugins to remove
            var dataValidationPluginsToRemove =
                BindingPlugins.DataValidators.OfType<DataAnnotationsValidationPlugin>().ToArray();

            // remove each entry found
            foreach (var plugin in dataValidationPluginsToRemove)
            {
                BindingPlugins.DataValidators.Remove(plugin);
            }
        }
    }
}