Class App

loader/App.xaml.cs:8–82

namespace PenguLoader
{
    public partial class App : Application
    {
        protected override void OnStartup(StartupEventArgs e)
        {
            base.OnStartup(e);
            SetLanguage(Config.Language);
        }

        public static event EventHandler LanguageChanged;
        public static string Language
        {
            get => Config.Language;
            set
            {
                if (value != Config.Language)
                {
                    Config.Language = value;
                    SetLanguage(value);
                    LanguageChanged?.Invoke(null, EventArgs.Empty);
                }
            }
        }

        public static string[] Languages
        {
            get
            {
                var keys = LanguageMap.Keys;
                var languages = new string[keys.Count];
                keys.CopyTo(languages, 0);
                return languages;
            }
        }

        static readonly Dictionary<string, string> LanguageMap = new Dictionary<string, string>
        {
            { "English", "en-US.xaml" },
            { "Tiếng Việt", "vi-VN.xaml" },
            { "日本語", "ja-JP.xaml" },
            { "中文", "zh-CN.xaml" },
            { "Deutsch", "de-DE.xaml" },
            { "Español", "es-ES.xaml" },
            { "Français", "fr-FR.xaml"},
            { "Português", "pt-BR.xaml" },
            { "Русский", "ru-RU.xaml" },
            { "Türkçe", "tr-TR.xaml" }
        };

        public static void SetLanguage(string lang)
        {
            if (!LanguageMap.ContainsKey(lang))
                lang = "English";

            var dict = new ResourceDictionary();
            var file = LanguageMap[lang];
            dict.Source = new Uri($"Languages/{file}", UriKind.Relative);

            Current.Resources.MergedDictionaries.Add(dict);