HandyControl/src/Avalonia/HandyControlDemo_Avalonia/App.axaml.cs

using System.Globalization;
using System.Linq;
using Avalonia;
using Avalonia.Controls.ApplicationLifetimes;
using Avalonia.Data.Core.Plugins;
using Avalonia.Markup.Xaml;


namespace HandyControlDemo;

public class App : Application
{
    public override void Initialize()
    {
        AvaloniaXamlLoader.Load(this);
    }

    public override void OnFrameworkInitializationCompleted()
    {
        Properties.Langs.Lang.Culture = new CultureInfo("en");
        RemoveDefaultDataValidator();

        if (ApplicationLifetime is IClassicDesktopStyleApplicationLifetime desktop)
        {
            desktop.MainWindow = new MainWindow();
        }

        base.OnFrameworkInitializationCompleted();
    }

    private static void RemoveDefaultDataValidator()
    {
        // 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);
        }
    }
}