The Language does not change in the ASP.NET Core Web application

Question

I follow the Globalization and localization and Building simple multilingual ASP.NET Core website tutorials to add a language switch for my application.

So, I created a partial view

@using Microsoft.AspNetCore.Builder
@using Microsoft.AspNetCore.Http.Features
@using Microsoft.AspNetCore.Localization
@using Microsoft.AspNetCore.Mvc.Localization
@using Microsoft.Extensions.Options

@inject IViewLocalizer Localizer
@inject IOptions<RequestLocalizationOptions> LocOptions

@{
    var requestCulture = Context.Features.Get<IRequestCultureFeature>();
    var cultureItems = LocOptions.Value.SupportedUICultures
        .Select(c => new SelectListItem { Value = c.Name, Text = c.DisplayName })
        .ToList();
}

<div title="@Localizer["Request culture provider:"] @requestCulture?.Provider?.GetType().Name">
    <form id="selectLanguage" asp-controller="Home"
          asp-action="SetLanguage" asp-route-returnUrl="@Context.Request.Path"
          method="post" class="form-horizontal" role="form">
        @Localizer["Language:"] 
        <select name="culture"
                onchange="this.form.submit();"
                asp-for="@requestCulture.RequestCulture.UICulture.Name" asp-items="cultureItems"></select>
    </form>
</div>

Added in the footer of the _Layout the

<div class="col-md-6 text-right">
    @await Html.PartialAsync("_SelectLanguagePartial")
</div>

and configure the Startup.cs like this:

services.AddLocalization(options => options.ResourcesPath = "Resources");

services.AddMvc()
    .AddViewLocalization(LanguageViewLocationExpanderFormat.Suffix)
    .AddDataAnnotationsLocalization();

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

    options.DefaultRequestCulture = new RequestCulture(culture: "es", uiCulture: "es");
    options.SupportedCultures = supportedCultures;
    options.SupportedUICultures = supportedCultures;    

});

I added a Resources folder and in it the

Views.Home.Index.es.resx
Views.Home.Index.en.resx
Views.Shared._Layout.es.resx
Views.Shared._Layout.en.resx

I also did Install-Package Microsoft.AspNetCore.Authentication.Cookies

When I load the Home View I have the Spanish option selected. But when I try to select "English" it loads, but rolls-back the Spanish version, so I can't finally see my content in English. Where is the problem?

Answer 1

Did you add javascript to make the language selector postback?

(function () {
$("#selectLanguage select").change(function () {
    $(this).parent().submit();
});
}());

Did you wire up therequest localization middleware in Configure?

var locOptions= app.ApplicationServices.GetService<IOptions<RequestLocalizationOptions>>();
app.UseRequestLocalization(locOptions.Value);

Did you add a method in HomeController like this:

[HttpPost]
public IActionResult SetLanguage(string culture, string returnUrl)
{
    Response.Cookies.Append(
        CookieRequestCultureProvider.DefaultCookieName,
        CookieRequestCultureProvider.MakeCookieValue(new RequestCulture(culture)),
        new CookieOptions { Expires = DateTimeOffset.UtcNow.AddYears(1) }
    );

    return LocalRedirect(returnUrl);
}