How to manually set the Culture during a ASP.NET Core MVC request?

Question

I'm looking for something similar like the old behaviour of setting the Culture and everything in the request after that has that Culture.

Similar like ASP.NET 4.5:

Thread.CurrentThread.CurrentCulture     = culture_info; 
Thread.CurrentThread.CurrentUICulture   = culture_info;

When I do this right now, some code seems to be constantly resetting the Culture to English at various points in the MVC pipeline.

Why do I want that? Because I want to set the culture through my extended routing logic in a very large (and customizable) platform-type of web project.

The default RouteDataRequestCultureProvider doesn't seem to work at all - see explained here:

https://irensaltali.com/en/asp-net-core-mvc-localization-by-url-routedatarequestcultureprovider/

and

Localization works when culture is set via QueryString but not when culture is in route

I don't want to use the "hardcoded" url parsing that is being presented as a solution, because my routing logic is complicated - not all routes will have a culture defined in the same spot in the URL.

I tried setting this, but that also didn't work:

httpContext.Features.Set<IRequestCultureFeature>(new RequestCultureFeature(request_culture, new DummyProvider()));

Is there any workaround for just simply setting the Culture for the rest of the request?

Answer 1

A workaround for simply setting the Culture for the rest of the request is to use default QueryStringRequestCultureProvider.

Here is the whole demo:

Startup.cs:

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

    services.AddControllersWithViews()
            .AddViewLocalization(LanguageViewLocationExpanderFormat.Suffix)
            .AddDataAnnotationsLocalization();
    //...
}
public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{
    var supportedCultures = new[]
    {
        new CultureInfo("en-US"),
        new CultureInfo("de"),
        new CultureInfo("fr"),
    };

    app.UseRequestLocalization(new RequestLocalizationOptions
    {
        DefaultRequestCulture = new RequestCulture("en-US"),
        // Formatting numbers, dates, etc.
        SupportedCultures = supportedCultures,
        // UI strings that we have localized.
        SupportedUICultures = supportedCultures
    });

    app.UseHttpsRedirection();
    app.UseStaticFiles();
    app.UseRouting();

    app.UseAuthorization();

    app.UseEndpoints(endpoints =>
    {
        endpoints.MapControllerRoute(
        name: "default",
        pattern: "{controller=Home}/{action=Index}/{id?}");
    });
}

Create Resource folder and add resource file as below:

Configure resource file like below:

Controllers.HomeController.de.resx

Controllers.HomeController.fr.resx

Reference:Resource file naming

Controller:

public class HomeController : Controller
{
    private readonly IStringLocalizer<HomeController> _localizer;

    public HomeController(IStringLocalizer<HomeController> localizer)
    {
        _localizer = localizer;
    }

    public IActionResult Index()
    {
        ViewData["Title"] = _localizer["Your Title"];
        return View();
    }
}

Index.cshtml:

@ViewData["Title"]

Result: