Localization for Blazor WASM (#17569)

Author: guardrex

aspnetcore/blazor/globalization-localization.md

@@ -5,7 +5,7 @@ description: Learn how to make Razor components accessible to users in multiple
 monikerRange: '>= aspnetcore-3.1'
 ms.author: riande
 ms.custom: mvc
-ms.date: 02/12/2020
+ms.date: 04/02/2020
 no-loc: [Blazor, SignalR]
 uid: blazor/globalization-localization
 ---
@@ -52,6 +52,18 @@ The following field types have specific formatting requirements and aren't curre
 
 ## Localization
 
+### Blazor WebAssembly
+
+Blazor WebAssembly apps set the culture using the user's [language preference](https://developer.mozilla.org/docs/Web/API/NavigatorLanguage/languages).
+
+To explicitly configure the culture, set `CultureInfo.DefaultThreadCurrentCulture` and `CultureInfo.DefaultThreadCurrentUICulture` in `Program.Main`.
+
+By default, Blazor's linker configuration for Blazor WebAssembly apps strips out internationalization information except for locales explicitly requested. For more information and guidance on controlling the linker's behavior, see <xref:host-and-deploy/blazor/configure-linker#configure-the-linker-for-internationalization>.
+
+While the culture that Blazor selects by default might be sufficient for most users, consider offering a way for users to specify their preferred locale. For a Blazor WebAssembly sample app with a culture picker, see the [LocSample](https://github.com/pranavkm/LocSample) localization sample app.
+
+### Blazor Server
+
 Blazor Server apps are localized using [Localization Middleware](xref:fundamentals/localization#localization-middleware). The middleware selects the appropriate culture for users requesting resources from the app.
 
 The culture can be set using one of the following approaches:
@@ -61,19 +73,15 @@ The culture can be set using one of the following approaches:
 
 For more information and examples, see <xref:fundamentals/localization>.
 
-### Configure the linker for internationalization (Blazor WebAssembly)
-
-By default, Blazor's linker configuration for Blazor WebAssembly apps strips out internationalization information except for locales explicitly requested. For more information and guidance on controlling the linker's behavior, see <xref:host-and-deploy/blazor/configure-linker#configure-the-linker-for-internationalization>.
-
-### Cookies
+#### Cookies
 
 A localization culture cookie can persist the user's culture. The cookie is created by the `OnGet` method of the app's host page (*Pages/Host.cshtml.cs*). The Localization Middleware reads the cookie on subsequent requests to set the user's culture. 
 
 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, use of a localization culture cookie is the recommended approach.
 
 Any technique can be used to assign a culture if the culture is persisted in a localization cookie. If the app already has an established localization scheme for server-side ASP.NET Core, continue to use the app's existing localization infrastructure and set the localization culture cookie within the app's scheme.
 
-The following example shows how to set the current culture in a cookie that can be read by the Localization Middleware. Create a *Pages/Host.cshtml.cs* file with the following contents in the Blazor Server app:
+The following example shows how to set the current culture in a cookie that can be read by the Localization Middleware. Create a *Pages/_Host.cshtml.cs* file with the following contents in the Blazor Server app:
 
 ```csharp
 public class HostModel : PageModel
@@ -99,9 +107,9 @@ Localization is handled by the app in the following sequence of events:
 1. The Localization Middleware reads the cookie and assigns the culture.
 1. The Blazor Server session begins with the correct culture.
 
-### Provide UI to choose the culture
+#### Provide UI to choose the culture
 
-To provide UI to allow a user to select a culture, a *redirect-based approach* is recommended. The process is similar to what happens in a web app when a user attempts to access a secure resource&mdash;the user is redirected to a sign-in page and then redirected back to the original resource. 
+To provide UI to allow a user to select a culture, a *redirect-based approach* is recommended. The process is similar to what happens in a web app when a user attempts to access a secure resource. The user is redirected to a sign-in page and then redirected back to the original resource. 
 
 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.