App.axaml.cs

using Avalonia;
using Avalonia.Controls.ApplicationLifetimes;
using Avalonia.Data.Core.Plugins;
using Avalonia.Markup.Xaml;
using HLC.Net.Setting;
using HLC.Net.ViewModels;
using HLC.Net.Views;
using System.Globalization;
namespace HLC.Net;
public partial class App : Application
{
    public override void Initialize() => AvaloniaXamlLoader.Load(this);

    public override void OnFrameworkInitializationCompleted()
    {
        SettingManager.LoadSettings();
        Assets.Resources.Culture = new CultureInfo(UserSetting.Language);
        if (ApplicationLifetime is IClassicDesktopStyleApplicationLifetime desktop)
        {
            // Line below is needed to remove Avalonia data validation.
            // Without this line you will get duplicate validations from both Avalonia and CT
            BindingPlugins.DataValidators.RemoveAt(0);
            desktop.MainWindow = new MainWindow
            {
                DataContext = new MainWindowViewModel()
            };
        }
        base.OnFrameworkInitializationCompleted();
    }
}