Why app returns only one supported culture?

Question

I try create language switch on my site. I've add cultures in Startup:

IList<CultureInfo> supportedCultures = new List<CultureInfo>
{
    new CultureInfo("ru"),
    new CultureInfo("uk"),
};
var localizationOptions = new RequestLocalizationOptions
{
    DefaultRequestCulture = new RequestCulture("uk"),
    SupportedCultures = supportedCultures,
    SupportedUICultures = supportedCultures
};
var requestProvider = new RouteDataRequestCultureProvider();
localizationOptions.RequestCultureProviders.Insert(0, requestProvider);
app.UseRequestLocalization(localizationOptions);

Localization works. But when I tried get list of supported cultures in Razor, it returns only one culture.
_{(source: mykmykpet.xyz)}

What am I doing wrong?

Answer 1

public class Startup
{
    public Startup(IConfiguration configuration, IHostingEnvironment environment)
    {
        Configuration = configuration;
        HostingEnvironment = environment;
    }

    public IConfiguration Configuration { get; }
    public IHostingEnvironment HostingEnvironment { get; }

    public void ConfigureServices(IServiceCollection services)
    {
        services.AddLocalization(options => options.ResourcesPath = "Resources");

        services.AddMvc()
            .SetCompatibilityVersion(CompatibilityVersion.Version_2_1)
            .AddViewLocalization(LanguageViewLocationExpanderFormat.Suffix)
            .AddDataAnnotationsLocalization();

        services.Configure<RequestLocalizationOptions>(options =>
        {
            var supportedCultures = new[]
            {
                new CultureInfo("ru"),
                new CultureInfo("uk")
            };

            options.DefaultRequestCulture = new RequestCulture("uk");
            options.SupportedCultures = supportedCultures;
            options.SupportedUICultures = supportedCultures;
            options.RequestCultureProviders.Insert(0, new RouteDataRequestCultureProvider());
        });
    }

    public void Configure(IApplicationBuilder app, IHostingEnvironment env)
    {
        var localizationOptions= app.ApplicationServices.GetService<IOptions<RequestLocalizationOptions>>().Value;
        app.UseRequestLocalization(localizationOptions);
    }
}