AspNetCore.Docs/aspnetcore/blazor/globalization-localization.md

title	author	description	monikerRange	ms.author	ms.custom	ms.date	uid	zone_pivot_groups
ASP.NET Core Blazor globalization and localization	guardrex	Learn how to render globalized and localized content to users in different cultures and languages.	>= aspnetcore-3.1	riande	mvc	11/08/2022	blazor/globalization-localization	blazor-hosting-models

ASP.NET Core Blazor globalization and localization

[!INCLUDE]

:::zone pivot="server"

This article explains how to render globalized and localized content to users in different cultures and languages in a Blazor Server app. See the Blazor WebAssembly version of this article for guidance on standalone and hosted Blazor WebAssembly apps.

:::zone-end

:::zone pivot="webassembly"

This article explains how to render globalized and localized content to users in different cultures and languages in a standalone or hosted (:::no-loc text="Client"::: project) Blazor WebAssembly app. See the Blazor Server version of this article for guidance on Blazor Server apps.

:::zone-end

For globalization, Blazor provides number and date formatting. For localization, Blazor renders content using the .NET Resources system.

A limited set of ASP.NET Core's localization features are supported:

✔️Supported: xref:Microsoft.Extensions.Localization.IStringLocalizer and xref:Microsoft.Extensions.Localization.IStringLocalizer%601 are supported in Blazor apps.

❌Not supported: xref:Microsoft.AspNetCore.Mvc.Localization.IHtmlLocalizer, xref:Microsoft.AspNetCore.Mvc.Localization.IViewLocalizer, and Data Annotations localization are ASP.NET Core MVC features and not supported in Blazor apps.

This article describes how to use Blazor's globalization and localization features based on:

• The Accept-Language header, which is set by the browser based on a user's language preferences in browser settings.
• A culture set by the app not based on the value of the Accept-Language header. The setting can be static for all users or dynamic based on app logic. When the setting is based on the user's preference, the setting is usually saved for reload on future visits.

For additional general information, see the following resources:

• xref:fundamentals/localization
• .NET Fundamentals: Globalization
• .NET Fundamentals: Localization

Often, the terms language and culture are used interchangeably when dealing with globalization and localization concepts.

In this article, language refers to selections made by a user in their browser's settings. The user's language selections are submitted in browser requests in the Accept-Language header. Browser settings usually use the word "language" in the UI.

Culture pertains to members of .NET and Blazor API. For example, a user's request can include the Accept-Language header specifying a language from the user's perspective, but the app ultimately sets the xref:System.Globalization.CultureInfo.CurrentCulture ("culture") property from the language that the user requested. API usually uses the word "culture" in its member names.

[!NOTE] The code examples in this article adopt nullable reference types (NRTs) and .NET compiler null-state static analysis, which are supported in ASP.NET Core 6.0 or later. When targeting ASP.NET Core 5.0 or earlier, remove the null type designation (?) from the article's examples.

Globalization

The @bind attribute directive applies formats and parses values for display based on the user's first preferred language that the app supports. @bind supports the @bind:culture parameter to provide a xref:System.Globalization.CultureInfo?displayProperty=fullName for parsing and formatting a value.

The current culture can be accessed from the xref:System.Globalization.CultureInfo.CurrentCulture?displayProperty=fullName property.

xref:System.Globalization.CultureInfo.InvariantCulture?displayProperty=nameWithType is used for the following field types (<input type="{TYPE}" />, where the {TYPE} placeholder is the type):

• date
• number

The preceding field types:

• Are displayed using their appropriate browser-based formatting rules.
• Can't contain free-form text.
• Provide user interaction characteristics based on the browser's implementation.

When using the date and number field types, specifying a culture with @bind:culture isn't recommended because Blazor provides built-in support to render values in the current culture.

The following field types have specific formatting requirements and aren't currently supported by Blazor because they aren't supported by all of the major browsers:

• datetime-local
• month
• week

For current browser support of the preceding types, see Can I use.

:::moniker range=">= aspnetcore-8.0"

:::zone pivot="webassembly"

.NET globalization and International Components for Unicode (ICU) support

Blazor WebAssembly uses a reduced globalization API and set of built-in International Components for Unicode (ICU) locales. For more information, see .NET globalization and ICU: ICU on WebAssembly.

To load a custom ICU data file to control the app's locales, see WASM Globalization Icu. Currently, manually building the custom ICU data file is required. .NET tooling to ease the process of creating the file is planned for a future .NET 8.0 preview release.

:::zone-end

:::moniker-end

:::moniker range="< aspnetcore-8.0"

:::zone pivot="webassembly"

.NET globalization and International Components for Unicode (ICU) support

Blazor WebAssembly uses a reduced globalization API and set of built-in International Components for Unicode (ICU) locales. For more information, see .NET globalization and ICU: ICU on WebAssembly.

Loading a custom subset of locales in a Blazor WebAssembly app is supported in .NET 8 or later. For more information, access this section for an 8.0 or later version of this article.

:::zone-end

:::moniker-end

Invariant globalization

If the app doesn't require localization, configure the app to support the invariant culture, which is generally based on United States English (en-US). Set the InvariantGlobalization property to true in the app's project file (.csproj):

<PropertyGroup>
  <InvariantGlobalization>true</InvariantGlobalization>
</PropertyGroup>

Alternatively, configure invariant globalization with the following approaches:

• In runtimeconfig.json:

  {
    "runtimeOptions": {
      "configProperties": {
        "System.Globalization.Invariant": true
      }
    }
  }
  

• With an environment variable:

  • Key: DOTNET_SYSTEM_GLOBALIZATION_INVARIANT
  • Value: true or 1

For more information, see Runtime configuration options for globalization (.NET documentation).

Demonstration component

The following CultureExample1 component can be used to demonstrate Blazor globalization and localization concepts covered by this article.

Pages/CultureExample1.razor:

@page "/culture-example-1"
@using System.Globalization

<h1>Culture Example 1</h1>

<p>
    <b>CurrentCulture</b>: @CultureInfo.CurrentCulture
</p>

<h2>Rendered values</h2>

<ul>
    <li><b>Date</b>: @dt</li>
    <li><b>Number</b>: @number.ToString("N2")</li>
</ul>

<h2><code>&lt;input&gt;</code> elements that don't set a <code>type</code></h2>

<p>
    The following <code>&lt;input&gt;</code> elements use
    <code>CultureInfo.CurrentCulture</code>.
</p>

<ul>
    <li><label><b>Date:</b> <input @bind="dt" /></label></li>
    <li><label><b>Number:</b> <input @bind="number" /></label></li>
</ul>

<h2><code>&lt;input&gt;</code> elements that set a <code>type</code></h2>

<p>
    The following <code>&lt;input&gt;</code> elements use
    <code>CultureInfo.InvariantCulture</code>.
</p>

<ul>
    <li><label><b>Date:</b> <input type="date" @bind="dt" /></label></li>
    <li><label><b>Number:</b> <input type="number" @bind="number" /></label></li>
</ul>

@code {
    private DateTime dt = DateTime.Now;
    private double number = 1999.69;
}

The number string format (N2) in the preceding example (.ToString("N2")) is a standard .NET numeric format specifier. The N2 format is supported for all numeric types, includes a group separator, and renders up to two decimal places.

Optionally, add a menu item to the navigation in Shared/NavMenu.razor for the CultureExample1 component.

Dynamically set the culture from the Accept-Language header

The Accept-Language header is set by the browser and controlled by the user's language preferences in browser settings. In browser settings, a user sets one or more preferred languages in order of preference. The order of preference is used by the browser to set quality values (q, 0-1) for each language in the header. The following example specifies United States English, English, and Chilean Spanish with a preference for United States English or English:

Accept-Language: en-US,en;q=0.9,es-CL;q=0.8

The app's culture is set by matching the first requested language that matches a supported culture of the app.

:::zone pivot="webassembly"

:::moniker range=">= aspnetcore-5.0"

Set the BlazorWebAssemblyLoadAllGlobalizationData property to true in the app's project file (.csproj):

<PropertyGroup>
  <BlazorWebAssemblyLoadAllGlobalizationData>true</BlazorWebAssemblyLoadAllGlobalizationData>
</PropertyGroup>

:::moniker-end

[!NOTE] If the app's specification requires limiting the supported cultures to an explicit list, see the Dynamically set the culture by user preference section of this article.

:::zone-end

:::zone pivot="server"

Blazor Server apps are localized using Localization Middleware. Add localization services to the app with xref:Microsoft.Extensions.DependencyInjection.LocalizationServiceCollectionExtensions.AddLocalization%2A.

In Program.cs:

builder.Services.AddLocalization();

Specify the app's supported cultures in Program.cs immediately after Routing Middleware is added to the processing pipeline. The following example configures supported cultures for United States English and Chilean Spanish:

app.UseRequestLocalization(new RequestLocalizationOptions()
    .AddSupportedCultures(new[] { "en-US", "es-CL" })
    .AddSupportedUICultures(new[] { "en-US", "es-CL" }));

For information on ordering the Localization Middleware in the middleware pipeline of Program.cs, see xref:fundamentals/middleware/index#middleware-order.

:::zone-end

Use the CultureExample1 component shown in the Demonstration component section to study how globalization works. Issue a request with United States English (en-US). Switch to Chilean Spanish (es-CL) in the browser's language settings. Request the webpage again.

[!NOTE] Some browsers force you to use the default language setting for both requests and the browser's own UI settings. This can make changing the language back to one that you understand difficult because all of the setting UI screens might end up in a language that you can't read. A browser such as Opera is a good choice for testing because it permits you to set a default language for webpage requests but leave the browser's settings UI in your language.

When the culture is United States English (en-US), the rendered component uses month/day date formatting (6/7), 12-hour time (AM/PM), and comma separators in numbers with a dot for the decimal value (1,999.69):

• Date: 6/7/2021 6:45:22 AM
• Number: 1,999.69

When the culture is Chilean Spanish (es-CL), the rendered component uses day/month date formatting (7/6), 24-hour time, and period separators in numbers with a comma for the decimal value (1.999,69):

• Date: 7/6/2021 6:49:38
• Number: 1.999,69

Statically set the culture

:::zone pivot="webassembly"

:::moniker range=">= aspnetcore-5.0"

Set the BlazorWebAssemblyLoadAllGlobalizationData property to true in the app's project file (.csproj):

<PropertyGroup>
  <BlazorWebAssemblyLoadAllGlobalizationData>true</BlazorWebAssemblyLoadAllGlobalizationData>
</PropertyGroup>

:::moniker-end

:::moniker range="< aspnetcore-5.0"

By default, the Intermediate Language (IL) Linker configuration for Blazor WebAssembly apps strips out internationalization information except for locales explicitly requested. For more information, see xref:blazor/host-and-deploy/configure-linker#configure-the-linker-for-internationalization.

:::moniker-end

The app's culture can be set in JavaScript when Blazor starts with the applicationCulture Blazor start option. The following example configures the app to launch using the United States English (en-US) culture.

• In wwwroot/index.html, prevent Blazor autostart by adding autostart="false" to Blazor's <script> tag:

  <script src="_framework/blazor.webassembly.js" autostart="false"></script>
  

• Add the following <script> block after Blazor's <script> tag and before the closing </body> tag:

  <script>
    Blazor.start({
      applicationCulture: 'en-US'
    });
  </script>
  

The value for applicationCulture must conform to the BCP-47 language tag format. For more information on Blazor startup, see xref:blazor/fundamentals/startup.

An alternative to setting the culture Blazor's start option is to set the culture in C# code. Set xref:System.Globalization.CultureInfo.DefaultThreadCurrentCulture?displayProperty=nameWithType and xref:System.Globalization.CultureInfo.DefaultThreadCurrentUICulture?displayProperty=nameWithType in Program.cs to the same culture.

Add the xref:System.Globalization?displayProperty=fullName namespace to Program.cs:

using System.Globalization;

Add the culture settings before the line that builds and runs the xref:Microsoft.AspNetCore.Components.WebAssembly.Hosting.WebAssemblyHostBuilder (await builder.Build().RunAsync();):

CultureInfo.DefaultThreadCurrentCulture = new CultureInfo("en-US");
CultureInfo.DefaultThreadCurrentUICulture = new CultureInfo("en-US");

[!IMPORTANT] Always set xref:System.Globalization.CultureInfo.DefaultThreadCurrentCulture and xref:System.Globalization.CultureInfo.DefaultThreadCurrentUICulture to the same culture in order to use xref:Microsoft.Extensions.Localization.IStringLocalizer and xref:Microsoft.Extensions.Localization.IStringLocalizer%601.

:::zone-end

:::zone pivot="server"

:::moniker range=">= aspnetcore-6.0"

Blazor Server apps are localized using Localization Middleware. Add localization services to the app with xref:Microsoft.Extensions.DependencyInjection.LocalizationServiceCollectionExtensions.AddLocalization%2A.

In Program.cs:

builder.Services.AddLocalization();

Specify the static culture in Program.cs immediately after Routing Middleware is added to the processing pipeline. The following example configures United States English:

app.UseRequestLocalization("en-US");

The culture value for xref:Microsoft.AspNetCore.Builder.ApplicationBuilderExtensions.UseRequestLocalization%2A must conform to the BCP-47 language tag format.

For information on ordering the Localization Middleware in the middleware pipeline of Program.cs, see xref:fundamentals/middleware/index#middleware-order.

:::moniker-end

:::moniker range="< aspnetcore-6.0"

Blazor Server apps are localized using Localization Middleware. Add localization services to the app with xref:Microsoft.Extensions.DependencyInjection.LocalizationServiceCollectionExtensions.AddLocalization%2A.

In Startup.ConfigureServices (Startup.cs):

services.AddLocalization();

Specify the static culture in Startup.Configure (Startup.cs) immediately after Routing Middleware is added to the processing pipeline. The following example configures United States English:

app.UseRequestLocalization("en-US");

The culture value for xref:Microsoft.AspNetCore.Builder.ApplicationBuilderExtensions.UseRequestLocalization%2A must conform to the BCP-47 language tag format.

For information on ordering the Localization Middleware in the middleware pipeline of Startup.Configure, see xref:fundamentals/middleware/index#middleware-order.

:::moniker-end

:::zone-end

Use the CultureExample1 component shown in the Demonstration component section to study how globalization works. Issue a request with United States English (en-US). Switch to Chilean Spanish (es-CL) in the browser's language settings. Request the webpage again. When the requested language is Chilean Spanish, the app's culture remains United States English (en-US).

Dynamically set the culture by user preference

:::zone pivot="webassembly"

Examples of locations where an app might store a user's preference include in browser local storage (common in Blazor WebAssembly apps), in a localization cookie or database (common in Blazor Server apps), or in an external service attached to an external database and accessed by a web API. The following example demonstrates how to use browser local storage.

Add the Microsoft.Extensions.Localization package to the app.

[!INCLUDE]

:::moniker range=">= aspnetcore-5.0"

Set the BlazorWebAssemblyLoadAllGlobalizationData property to true in the project file:

<PropertyGroup>
  <BlazorWebAssemblyLoadAllGlobalizationData>true</BlazorWebAssemblyLoadAllGlobalizationData>
</PropertyGroup>

:::moniker-end

The app's culture in a Blazor WebAssembly app is set using the Blazor framework's API. A user's culture selection can be persisted in browser local storage.

In the wwwroot/index.html file after Blazor's <script> tag and before the closing </body> tag, provide JS functions to get and set the user's culture selection with browser local storage:

<script>
  window.blazorCulture = {
    get: () => window.localStorage['BlazorCulture'],
    set: (value) => window.localStorage['BlazorCulture'] = value
  };
</script>

:::moniker range=">= aspnetcore-5.0"

[!NOTE] The preceding example pollutes the client with global methods. For a better approach in production apps, see JavaScript isolation in JavaScript modules.

:::moniker-end

Add the namespaces for xref:System.Globalization?displayProperty=fullName and xref:Microsoft.JSInterop?displayProperty=fullName to the top of Program.cs:

using System.Globalization;
using Microsoft.JSInterop;

Remove the following line from Program.cs:

- await builder.Build().RunAsync();

Replace the preceding line with the following code. The code adds Blazor's localization service to the app's service collection with xref:Microsoft.Extensions.DependencyInjection.LocalizationServiceCollectionExtensions.AddLocalization%2A and uses JS interop to call into JS and retrieve the user's culture selection from local storage. If local storage doesn't contain a culture for the user, the code sets a default value of United States English (en-US).

builder.Services.AddLocalization();

var host = builder.Build();

CultureInfo culture;
var js = host.Services.GetRequiredService<IJSRuntime>();
var result = await js.InvokeAsync<string>("blazorCulture.get");

if (result != null)
{
    culture = new CultureInfo(result);
}
else
{
    culture = new CultureInfo("en-US");
    await js.InvokeVoidAsync("blazorCulture.set", "en-US");
}

CultureInfo.DefaultThreadCurrentCulture = culture;
CultureInfo.DefaultThreadCurrentUICulture = culture;

await host.RunAsync();

[!IMPORTANT] Always set xref:System.Globalization.CultureInfo.DefaultThreadCurrentCulture and xref:System.Globalization.CultureInfo.DefaultThreadCurrentUICulture to the same culture in order to use xref:Microsoft.Extensions.Localization.IStringLocalizer and xref:Microsoft.Extensions.Localization.IStringLocalizer%601.

The following CultureSelector component shows how to perform the following actions:

• Set the user's culture selection into browser local storage via JS interop.
• Reload the component that they requested (forceLoad: true), which uses the updated culture.

The CultureSelector component is placed in the Shared folder for use throughout the app.

Shared/CultureSelector.razor:

@using  System.Globalization
@inject IJSRuntime JS
@inject NavigationManager Navigation

<p>
    <label>
        Select your locale:
        <select @bind="Culture">
            @foreach (var culture in supportedCultures)
            {
                <option value="@culture">@culture.DisplayName</option>
            }
        </select>
    </label>
</p>

@code
{
    private CultureInfo[] supportedCultures = new[]
    {
        new CultureInfo("en-US"),
        new CultureInfo("es-CL"),
    };

    private CultureInfo Culture
    {
        get => CultureInfo.CurrentCulture;
        set
        {
            if (CultureInfo.CurrentCulture != value)
            {
                var js = (IJSInProcessRuntime)JS;
                js.InvokeVoid("blazorCulture.set", value.Name);

                Navigation.NavigateTo(Navigation.Uri, forceLoad: true);
            }
        }
    }
}

[!NOTE] For more information on xref:Microsoft.JSInterop.IJSInProcessRuntime, see xref:blazor/js-interop/call-javascript-from-dotnet#synchronous-js-interop-in-blazor-webassembly-apps.

Inside the closing tag of the </main> element in Shared/MainLayout.razor, add the CultureSelector component:

<article class="bottom-row px-4">
    <CultureSelector />
</article>

:::zone-end

:::zone pivot="server"

Examples of locations where an app might store a user's preference include in browser local storage (common in Blazor WebAssembly apps), in a localization cookie or database (common in Blazor Server apps), or in an external service attached to an external database and accessed by a web API. The following example demonstrates how to use a localization cookie.

Add the Microsoft.Extensions.Localization package to the app.

[!INCLUDE]

Blazor Server apps are localized using Localization Middleware. Add localization services to the app with xref:Microsoft.Extensions.DependencyInjection.LocalizationServiceCollectionExtensions.AddLocalization%2A.

In Program.cs:

builder.Services.AddLocalization();

Set the app's default and supported cultures with xref:Microsoft.AspNetCore.Builder.RequestLocalizationOptions.

In Program.cs immediately after Routing Middleware is added to the processing pipeline:

var supportedCultures = new[] { "en-US", "es-CL" };
var localizationOptions = new RequestLocalizationOptions()
    .SetDefaultCulture(supportedCultures[0])
    .AddSupportedCultures(supportedCultures)
    .AddSupportedUICultures(supportedCultures);

app.UseRequestLocalization(localizationOptions);

For information on ordering the Localization Middleware in the middleware pipeline of Program.cs, see xref:fundamentals/middleware/index#middleware-order.

The following example shows how to set the current culture in a cookie that can be read by the Localization Middleware.

Modifications to the Pages/_Host.cshtml file require the following namespaces:

• xref:System.Globalization?displayProperty=fullName
• xref:Microsoft.AspNetCore.Localization?displayProperty=fullName

Pages/_Host.cshtml:

+ @using System.Globalization
+ @using Microsoft.AspNetCore.Localization
+ @{
+     this.HttpContext.Response.Cookies.Append(
+         CookieRequestCultureProvider.DefaultCookieName,
+         CookieRequestCultureProvider.MakeCookieValue(
+             new RequestCulture(
+                 CultureInfo.CurrentCulture,
+                 CultureInfo.CurrentUICulture)));
+ }

For information on ordering the Localization Middleware in the middleware pipeline of Program.cs, see xref:fundamentals/middleware/index#middleware-order.

If the app isn't configured to process controller actions:

• Add MVC services by calling xref:Microsoft.Extensions.DependencyInjection.MvcServiceCollectionExtensions.AddControllers%2A on the service collection in Program.cs:

  builder.Services.AddControllers();
  

• Add controller endpoint routing in Program.cs by calling xref:Microsoft.AspNetCore.Builder.ControllerEndpointRouteBuilderExtensions.MapControllers%2A on the xref:Microsoft.AspNetCore.Routing.IEndpointRouteBuilder:

  app.MapControllers();
  

  The following example shows the call to xref:Microsoft.AspNetCore.Builder.EndpointRoutingApplicationBuilderExtensions.UseEndpoints%2A after the line is added:

  app.MapControllers();
  app.MapBlazorHub();
  app.MapFallbackToPage("/_Host");
  

To provide UI to allow a user to select a culture, use a redirect-based approach with a localization cookie. The app persists the user's selected culture via a redirect to a controller. The controller sets the user's selected culture into a cookie and redirects the user back to the original URI. The process is similar to what happens in a web app when a user attempts to access a secure resource, where the user is redirected to a sign-in page and then redirected back to the original resource.

Controllers/CultureController.cs:

using Microsoft.AspNetCore.Localization;
using Microsoft.AspNetCore.Mvc;

[Route("[controller]/[action]")]
public class CultureController : Controller
{
    public IActionResult Set(string culture, string redirectUri)
    {
        if (culture != null)
        {
            HttpContext.Response.Cookies.Append(
                CookieRequestCultureProvider.DefaultCookieName,
                CookieRequestCultureProvider.MakeCookieValue(
                    new RequestCulture(culture, culture)));
        }

        return LocalRedirect(redirectUri);
    }
}

[!WARNING] Use the xref:Microsoft.AspNetCore.Mvc.ControllerBase.LocalRedirect%2A action result to prevent open redirect attacks. For more information, see xref:security/preventing-open-redirects.

The following CultureSelector component shows how to call the Set method of the CultureController with the new culture. The component is placed in the Shared folder for use throughout the app.

Shared/CultureSelector.razor:

@using  System.Globalization
@inject NavigationManager Navigation

<p>
    <label>
        Select your locale:
        <select @bind="Culture">
            @foreach (var culture in supportedCultures)
            {
                <option value="@culture">@culture.DisplayName</option>
            }
        </select>
    </label>
</p>

@code
{
    private CultureInfo[] supportedCultures = new[]
    {
        new CultureInfo("en-US"),
        new CultureInfo("es-CL"),
    };

    protected override void OnInitialized()
    {
        Culture = CultureInfo.CurrentCulture;
    }

    private CultureInfo Culture
    {
        get => CultureInfo.CurrentCulture;
        set
        {
            if (CultureInfo.CurrentCulture != value)
            {
                var uri = new Uri(Navigation.Uri)
                    .GetComponents(UriComponents.PathAndQuery, UriFormat.Unescaped);
                var cultureEscaped = Uri.EscapeDataString(value.Name);
                var uriEscaped = Uri.EscapeDataString(uri);

                Navigation.NavigateTo(
                    $"Culture/Set?culture={cultureEscaped}&redirectUri={uriEscaped}",
                    forceLoad: true);
            }
        }
    }
}

Inside the closing </main> tag in Shared/MainLayout.razor, add the CultureSelector component:

<article class="bottom-row px-4">
    <CultureSelector />
</article>

:::zone-end

Use the CultureExample1 component shown in the Demonstration component section to study how the preceding example works.

Localization

If the app doesn't already support culture selection per the Dynamically set the culture by user preference section of this article, add the Microsoft.Extensions.Localization package to the app.

[!INCLUDE]

:::zone pivot="webassembly"

:::moniker range=">= aspnetcore-5.0"

Set the BlazorWebAssemblyLoadAllGlobalizationData property to true in the app's project file (.csproj):

<PropertyGroup>
  <BlazorWebAssemblyLoadAllGlobalizationData>true</BlazorWebAssemblyLoadAllGlobalizationData>
</PropertyGroup>

:::moniker-end

In Program.cs, add namespace the namespace for xref:System.Globalization?displayProperty=fullName to the top of the file:

using System.Globalization;

Add Blazor's localization service to the app's service collection with xref:Microsoft.Extensions.DependencyInjection.LocalizationServiceCollectionExtensions.AddLocalization%2A in Program.cs:

builder.Services.AddLocalization();

:::zone-end

:::zone pivot="server"

Use Localization Middleware to set the app's culture.

If the app doesn't already support culture selection per the Dynamically set the culture by user preference section of this article:

:::moniker range=">= aspnetcore-6.0"

• Add localization services to the app with xref:Microsoft.Extensions.DependencyInjection.LocalizationServiceCollectionExtensions.AddLocalization%2A.
• Specify the app's default and supported cultures in Program.cs. The following example configures supported cultures for United States English and Chilean Spanish.

In Program.cs:

builder.Services.AddLocalization();

In Program.cs immediately after Routing Middleware is added to the processing pipeline:

var supportedCultures = new[] { "en-US", "es-CL" };
var localizationOptions = new RequestLocalizationOptions()
    .SetDefaultCulture(supportedCultures[0])
    .AddSupportedCultures(supportedCultures)
    .AddSupportedUICultures(supportedCultures);

app.UseRequestLocalization(localizationOptions);

For information on ordering the Localization Middleware in the middleware pipeline of Program.cs, see xref:fundamentals/middleware/index#middleware-order.

:::moniker-end

:::moniker range="< aspnetcore-6.0"

• Add localization services to the app with xref:Microsoft.Extensions.DependencyInjection.LocalizationServiceCollectionExtensions.AddLocalization%2A.
• Specify the app's default and supported cultures in Startup.Configure (Startup.cs). The following example configures supported cultures for United States English and Chilean Spanish.

In Startup.ConfigureServices (Startup.cs):

services.AddLocalization();

In Startup.Configure immediately after Routing Middleware is added to the processing pipeline:

var supportedCultures = new[] { "en-US", "es-CL" };
var localizationOptions = new RequestLocalizationOptions()
    .SetDefaultCulture(supportedCultures[0])
    .AddSupportedCultures(supportedCultures)
    .AddSupportedUICultures(supportedCultures);

app.UseRequestLocalization(localizationOptions);

For information on ordering the Localization Middleware in the middleware pipeline of Startup.Configure, see xref:fundamentals/middleware/index#middleware-order.

:::moniker-end

If the app should localize resources based on storing a user's culture setting, use a localization culture cookie. Use of a cookie ensures that the WebSocket connection can correctly propagate the culture. If localization schemes are based on the URL path or query string, the scheme might not be able to work with WebSockets, thus fail to persist the culture. Therefore, the recommended approach is to use a localization culture cookie. See the Dynamically set the culture by user preference section of this article to see an example Razor expression that persists the user's culture selection.

:::zone-end

The example of localized resources in this section works with the prior examples in this article where the app's supported cultures are English (en) as a default locale and Spanish (es) as a user-selectable or browser-specified alternate locale.

Create resources for each locale. In the following example, resources are created for a default Greeting string:

• English: Hello, World!
• Spanish (es): ¡Hola, Mundo!

[!NOTE] The following resource file can be added in Visual Studio by right-clicking the project's Pages folder and selecting Add > New Item > Resources File. Name the file CultureExample2.resx. When the editor appears, provide data for a new entry. Set the Name to Greeting and Value to Hello, World!. Save the file.

Pages/CultureExample2.resx:

<?xml version="1.0" encoding="utf-8"?>
<root>
  <xsd:schema id="root" xmlns="" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">
    <xsd:import namespace="http://www.w3.org/XML/1998/namespace" />
    <xsd:element name="root" msdata:IsDataSet="true">
      <xsd:complexType>
        <xsd:choice maxOccurs="unbounded">
          <xsd:element name="metadata">
            <xsd:complexType>
              <xsd:sequence>
                <xsd:element name="value" type="xsd:string" minOccurs="0" />
              </xsd:sequence>
              <xsd:attribute name="name" use="required" type="xsd:string" />
              <xsd:attribute name="type" type="xsd:string" />
              <xsd:attribute name="mimetype" type="xsd:string" />
              <xsd:attribute ref="xml:space" />
            </xsd:complexType>
          </xsd:element>
          <xsd:element name="assembly">
            <xsd:complexType>
              <xsd:attribute name="alias" type="xsd:string" />
              <xsd:attribute name="name" type="xsd:string" />
            </xsd:complexType>
          </xsd:element>
          <xsd:element name="data">
            <xsd:complexType>
              <xsd:sequence>
                <xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
                <xsd:element name="comment" type="xsd:string" minOccurs="0" msdata:Ordinal="2" />
              </xsd:sequence>
              <xsd:attribute name="name" type="xsd:string" use="required" msdata:Ordinal="1" />
              <xsd:attribute name="type" type="xsd:string" msdata:Ordinal="3" />
              <xsd:attribute name="mimetype" type="xsd:string" msdata:Ordinal="4" />
              <xsd:attribute ref="xml:space" />
            </xsd:complexType>
          </xsd:element>
          <xsd:element name="resheader">
            <xsd:complexType>
              <xsd:sequence>
                <xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
              </xsd:sequence>
              <xsd:attribute name="name" type="xsd:string" use="required" />
            </xsd:complexType>
          </xsd:element>
        </xsd:choice>
      </xsd:complexType>
    </xsd:element>
  </xsd:schema>
  <resheader name="resmimetype">
    <value>text/microsoft-resx</value>
  </resheader>
  <resheader name="version">
    <value>2.0</value>
  </resheader>
  <resheader name="reader">
    <value>System.Resources.ResXResourceReader, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
  </resheader>
  <resheader name="writer">
    <value>System.Resources.ResXResourceWriter, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
  </resheader>
  <data name="Greeting" xml:space="preserve">
    <value>Hello, World!</value>
  </data>
</root>

[!NOTE] The following resource file can be added in Visual Studio by right-clicking the project's Pages folder and selecting Add > New Item > Resources File. Name the file CultureExample2.es.resx. When the editor appears, provide data for a new entry. Set the Name to Greeting and Value to ¡Hola, Mundo!. Save the file.

Pages/CultureExample2.es.resx:

<?xml version="1.0" encoding="utf-8"?>
<root>
  <xsd:schema id="root" xmlns="" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">
    <xsd:import namespace="http://www.w3.org/XML/1998/namespace" />
    <xsd:element name="root" msdata:IsDataSet="true">
      <xsd:complexType>
        <xsd:choice maxOccurs="unbounded">
          <xsd:element name="metadata">
            <xsd:complexType>
              <xsd:sequence>
                <xsd:element name="value" type="xsd:string" minOccurs="0" />
              </xsd:sequence>
              <xsd:attribute name="name" use="required" type="xsd:string" />
              <xsd:attribute name="type" type="xsd:string" />
              <xsd:attribute name="mimetype" type="xsd:string" />
              <xsd:attribute ref="xml:space" />
            </xsd:complexType>
          </xsd:element>
          <xsd:element name="assembly">
            <xsd:complexType>
              <xsd:attribute name="alias" type="xsd:string" />
              <xsd:attribute name="name" type="xsd:string" />
            </xsd:complexType>
          </xsd:element>
          <xsd:element name="data">
            <xsd:complexType>
              <xsd:sequence>
                <xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
                <xsd:element name="comment" type="xsd:string" minOccurs="0" msdata:Ordinal="2" />
              </xsd:sequence>
              <xsd:attribute name="name" type="xsd:string" use="required" msdata:Ordinal="1" />
              <xsd:attribute name="type" type="xsd:string" msdata:Ordinal="3" />
              <xsd:attribute name="mimetype" type="xsd:string" msdata:Ordinal="4" />
              <xsd:attribute ref="xml:space" />
            </xsd:complexType>
          </xsd:element>
          <xsd:element name="resheader">
            <xsd:complexType>
              <xsd:sequence>
                <xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
              </xsd:sequence>
              <xsd:attribute name="name" type="xsd:string" use="required" />
            </xsd:complexType>
          </xsd:element>
        </xsd:choice>
      </xsd:complexType>
    </xsd:element>
  </xsd:schema>
  <resheader name="resmimetype">
    <value>text/microsoft-resx</value>
  </resheader>
  <resheader name="version">
    <value>2.0</value>
  </resheader>
  <resheader name="reader">
    <value>System.Resources.ResXResourceReader, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
  </resheader>
  <resheader name="writer">
    <value>System.Resources.ResXResourceWriter, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
  </resheader>
  <data name="Greeting" xml:space="preserve">
    <value>¡Hola, Mundo!</value>
  </data>
</root>

The following component demonstrates the use of the localized Greeting string with xref:Microsoft.Extensions.Localization.IStringLocalizer%601. The Razor markup @Loc["Greeting"] in the following example localizes the string keyed to the Greeting value, which is set in the preceding resource files.

Add the namespace for xref:Microsoft.Extensions.Localization?displayProperty=fullName to the app's _Imports.razor file:

@using Microsoft.Extensions.Localization

Pages/CultureExample2.razor:

@page "/culture-example-2"
@using System.Globalization
@inject IStringLocalizer<CultureExample2> Loc

<h1>Culture Example 2</h1>

<p>
    <b>CurrentCulture</b>: @CultureInfo.CurrentCulture
</p>

<h2>Greeting</h2>

<p>
    @Loc["Greeting"]
</p>

<p>
    @greeting
</p>

@code {
    private string? greeting;

    protected override void OnInitialized()
    {
        greeting = Loc["Greeting"];
    }
}

Optionally, add a menu item to the navigation in Shared/NavMenu.razor for the CultureExample2 component.

:::moniker range=">= aspnetcore-5.0"

:::zone pivot="webassembly"

Culture provider reference source

To further understand how the Blazor framework processes localization, see the WebAssemblyCultureProvider class in the ASP.NET Core reference source.

[!INCLUDE]

:::zone-end

:::moniker-end

Shared resources

To create localization shared resources, adopt the following approach.

• Create a dummy class with an arbitrary class name. In the following example:

  • The app uses the BlazorSample namespace, and localization assets use the BlazorSample.Localization namespace.
  • The dummy class is named SharedResource.
  • The class file is placed in a Localization folder at the root of the app.

  Localization/SharedResource.cs:

  namespace BlazorSample.Localization;
  
  public class SharedResource
  {
  }
  

• Create the shared resource files with a Build Action of Embedded resource. In the following example:

  • The files are placed in the Localization folder with the dummy SharedResource class (Localization/SharedResource.cs).

  • Name the resource files to match the name of the dummy class. The following example files include a default localization file and a file for Spanish (es) localization.

  • Localization/SharedResource.resx

  • Localization/SharedResource.es.resx

  [!NOTE] Localization is resource path that can be set via xref:Microsoft.Extensions.Localization.LocalizationOptions.

• To reference the dummy class for an injected xref:Microsoft.Extensions.Localization.IStringLocalizer%601 in a Razor component, either place an @using directive for the localization namespace or include the localization namespace in the dummy class reference. In the following examples:

  • The first example states the Localization namespace for the SharedResource dummy class with an @using directive.
  • The second example states the SharedResource dummy class's namespace explicitly.

  In a Razor component, use either of the following approaches:

  @using Localization
  @inject IStringLocalizer<SharedResource> Loc
  

  @inject IStringLocalizer<Localization.SharedResource> Loc
  

For additional guidance, see xref:fundamentals/localization.

Additional resources

• Set the app base path
• xref:fundamentals/localization
• Globalizing and localizing .NET applications
• Resources in .resx Files
• Microsoft Multilingual App Toolkit
• Localization & Generics
• Calling InvokeAsync(StateHasChanged) causes page to fallback to default culture (dotnet/aspnetcore #28521)