Update globalization-localization.md (#20239)

Author: ThomasPrioul

aspnetcore/blazor/globalization-localization.md

@@ -149,6 +149,19 @@ 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.
 
+When working with a <xref:Microsoft.AspNetCore.Mvc.Razor.RazorPage>, use the <xref:Microsoft.AspNetCore.Mvc.Razor.RazorPage.Context> property:
+
+```razor
+@{
+    this.Context.Response.Cookies.Append(
+        CookieRequestCultureProvider.DefaultCookieName,
+        CookieRequestCultureProvider.MakeCookieValue(
+            new RequestCulture(
+                CultureInfo.CurrentCulture,
+                CultureInfo.CurrentUICulture)));
+}
+```
+
 #### 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. The user is redirected to a sign-in page and then redirected back to the original resource.