Set default culture

Question

Set default culture

Kuler Master 406

Hello guys,

I am using Microsoft.Extensions.Localization (8.0.11) but for some reason the following code does not work as expected. As you see, I expect the German to be default language but it's always English. Am I missing something?

var supportedCultures = new[] { "de-DE", "en-US" }; 
var localizationOptions = new RequestLocalizationOptions()     
.SetDefaultCulture("de-DE")     
.AddSupportedCultures(supportedCultures)     
.AddSupportedUICultures(supportedCultures);

Thank you

AgaveJoe 30,206 Reputation points

2025-02-07T11:03:20.8433333+00:00

Where and when does the code block execute? Can you provide a working example so we can understand how your code works?

The official documentation has strategies for handling culture in a asp.net Core app. .https://learn.microsoft.com/en-us/aspnet/core/blazor/globalization-localization?view=aspnetcore-9.0

https://learn.microsoft.com/en-us/aspnet/core/fundamentals/localization/select-language-culture?view=aspnetcore-9.0
Kuler Master 406 Reputation points

2025-02-07T11:18:09.2433333+00:00
It's the code that is executed from within the Program.cs (Blazor 8.0)

builder.Services.AddLocalization();
AgaveJoe 30,206 Reputation points

2025-02-07T12:44:39.55+00:00

Order matter as explained in the official documentation.

The first step in troubleshooting is reproducing the unwanted behavior. Here on the forums, we cannot reproduce your unwanted behavior without sample code.

Kuler Master 406

I see nothing wrong with the order, but maybe I am missing something obvious. This is the Program.cs code

var builder = WebApplication.CreateBuilder(args);
builder.Logging.SetMinimumLevel(LogLevel.Warning);
if (builder.Environment.IsDevelopment())
{
    builder.Services.AddServerSideBlazor().AddCircuitOptions(x => x.DetailedErrors = true);
}
else
{
    builder.Services.AddServerSideBlazor();
}
#endregion
// Add services to the container.
builder.Services.AddRazorComponents()
    .AddInteractiveServerComponents();
builder.Services.AddHttpContextAccessor();
builder.Services.AddLocalization();
builder.Services.AddControllers();
builder.Services.AddBlazorBootstrap();
builder.Services.AddScoped<Identity>();
var app = builder.Build();
var supportedCultures = new[] { "de-DE", "en-US" };
var localizationOptions = new RequestLocalizationOptions()
    .SetDefaultCulture(supportedCultures[0])
    .AddSupportedCultures(supportedCultures)
    .AddSupportedUICultures(supportedCultures);
// Apply the localization settings before other middlewares.
app.UseRequestLocalization(localizationOptions);
app.UseMiddleware<LocalizationMiddleware>();
// Configure the HTTP request pipeline.
if (!app.Environment.IsDevelopment())
{
    app.UseExceptionHandler("/Error", createScopeForErrors: true);
    // The default HSTS value is 30 days. You may want to change this for production scenarios, see https://aka.ms/aspnetcore-hsts.
    app.UseHsts();
    
    app.UseRewriter(new RewriteOptions().AddRedirectToNonWwwPermanent().AddRedirectToHttps());
}
app.UseHttpsRedirection();
app.UseStaticFiles();
app.UseAntiforgery();
app.MapControllers();
app.MapRazorComponents<App>().AddInteractiveServerRenderMode();
app.Run();

Thank you!

Anonymous

2025-02-10T03:50:52.06+00:00

which language is set to your browser? could you try to add Console.WriteLine(CultureInfo.CurrentCulture.Name); and see which culture is set. i see you have custom middleware could share that code as well. try to add app.UseRequestLocalization() before app.UseMiddleware<LocalizationMiddleware>()
John 20 Reputation points

2025-02-10T16:49:59.6566667+00:00

I think the language that is set on the browser will load the corresponding culture (if defined). That's based on my experience, had the same issue.
John 20 Reputation points

2025-02-10T16:52:28.0766667+00:00

(sorry double)

1 answer

Your answer

AgaveJoe 30,206 Reputation points

2025-02-07T11:03:20.8433333+00:00

Where and when does the code block execute? Can you provide a working example so we can understand how your code works?

The official documentation has strategies for handling culture in a asp.net Core app. .https://learn.microsoft.com/en-us/aspnet/core/blazor/globalization-localization?view=aspnetcore-9.0

https://learn.microsoft.com/en-us/aspnet/core/fundamentals/localization/select-language-culture?view=aspnetcore-9.0
Kuler Master 406 Reputation points

2025-02-07T11:18:09.2433333+00:00

It's the code that is executed from within the Program.cs (Blazor 8.0)

builder.Services.AddLocalization();
AgaveJoe 30,206 Reputation points

2025-02-07T12:44:39.55+00:00

Order matter as explained in the official documentation.

The first step in troubleshooting is reproducing the unwanted behavior. Here on the forums, we cannot reproduce your unwanted behavior without sample code.
Kuler Master 406 Reputation points

2025-02-07T22:20:20.4033333+00:00

I see nothing wrong with the order, but maybe I am missing something obvious. This is the Program.cs code

var builder = WebApplication.CreateBuilder(args); builder.Logging.SetMinimumLevel(LogLevel.Warning); if (builder.Environment.IsDevelopment()) { builder.Services.AddServerSideBlazor().AddCircuitOptions(x => x.DetailedErrors = true); } else { builder.Services.AddServerSideBlazor(); } #endregion // Add services to the container. builder.Services.AddRazorComponents() .AddInteractiveServerComponents(); builder.Services.AddHttpContextAccessor(); builder.Services.AddLocalization(); builder.Services.AddControllers(); builder.Services.AddBlazorBootstrap(); builder.Services.AddScoped<Identity>(); var app = builder.Build(); var supportedCultures = new[] { "de-DE", "en-US" }; var localizationOptions = new RequestLocalizationOptions() .SetDefaultCulture(supportedCultures[0]) .AddSupportedCultures(supportedCultures) .AddSupportedUICultures(supportedCultures); // Apply the localization settings before other middlewares. app.UseRequestLocalization(localizationOptions); app.UseMiddleware<LocalizationMiddleware>(); // Configure the HTTP request pipeline. if (!app.Environment.IsDevelopment()) { app.UseExceptionHandler("/Error", createScopeForErrors: true); // The default HSTS value is 30 days. You may want to change this for production scenarios, see https://aka.ms/aspnetcore-hsts. app.UseHsts(); app.UseRewriter(new RewriteOptions().AddRedirectToNonWwwPermanent().AddRedirectToHttps()); } app.UseHttpsRedirection(); app.UseStaticFiles(); app.UseAntiforgery(); app.MapControllers(); app.MapRazorComponents<App>().AddInteractiveServerRenderMode(); app.Run();

Thank you!
Anonymous

2025-02-10T03:50:52.06+00:00

which language is set to your browser? could you try to add Console.WriteLine(CultureInfo.CurrentCulture.Name); and see which culture is set. i see you have custom middleware could share that code as well. try to add app.UseRequestLocalization() before app.UseMiddleware<LocalizationMiddleware>()
John 20 Reputation points

2025-02-10T16:49:59.6566667+00:00

I think the language that is set on the browser will load the corresponding culture (if defined). That's based on my experience, had the same issue.
John 20 Reputation points

2025-02-10T16:52:28.0766667+00:00

(sorry double)

Answer 1

Hi @Kuler Master ,

Here are a few recommendations and troubleshooting steps to help resolve this:

Verify Middleware Execution Order

The RequestLocalizationMiddleware must be registered before any middleware or components that rely on culture settings. From your shared Program.cs, it looks like you're applying it correctly, but double-check that it's placed before app.UseMiddleware<LocalizationMiddleware>() and any routing or endpoint configuration.

Ensure Culture Providers Are Not Overriding Defaults

ASP.NET Core uses a series of IRequestCultureProviders (e.g., query string, cookies, headers) to determine the culture. If any of these providers are active and detect a different culture (like en-US from browser headers), they will override your default.

Recommendation: Consider customizing or reordering the culture providers if you want to strictly enforce de-DE as the default unless explicitly overridden.

Check Browser Language Settings

Browsers often send Accept-Language headers that influence culture detection. If your browser is set to English, it may override the default.

Recommendation: Try testing with a browser set to German or temporarily remove the AcceptLanguageHeaderRequestCultureProvider from the provider list to isolate the issue.

Validate Resource Availability

Ensure that your .resx files for de-DE are correctly named and placed in the Resources folder. Missing or misnamed resource files can cause fallback to English.

Use Logging for Diagnostics

Add logging or debug output to confirm which culture is being applied during runtime:

Console.WriteLine($"CurrentCulture: {CultureInfo.CurrentCulture}");
Console.WriteLine($"CurrentUICulture: {CultureInfo.CurrentUICulture}");

For more information, you can check out these links:

https://learn.microsoft.com/en-us/aspnet/core/blazor/globalization-localization?view=aspnetcore-9.0

https://learn.microsoft.com/en-us/aspnet/core/fundamentals/localization/select-language-culture?view=aspnetcore-9.0

Hope my answer would help.

Jack Dang (WICLOUD CORPORATION) 1,020 Reputation points Microsoft External Staff

2025-07-14T02:18:15.25+00:00

I hope everything is going well on your side! Just checking in to see if my solution was helpful. Feel free to reach out if there's anything else I can assist with.
Jack Dang (WICLOUD CORPORATION) 1,020 Reputation points Microsoft External Staff

2025-08-11T08:45:23.3233333+00:00

Hi @Kuler Master ,

Just checking in — I haven’t heard back from you for a while, I hope everything works out as you expected.

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Set default culture

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