Add Localization Samples for .NET 8 (#34199)

* Add Localization & PO Localization samples for .NET 8

* Update markdown files

* Remove unnecessary files

Author: hishamco

aspnetcore/fundamentals/localization/make-content-localizable.md

@@ -23,7 +23,7 @@ One task for localizing an app is to wrap localizable content with code that fac
 
 The following code example shows how to wrap the string "About Title" for localization.
 
-[!code-csharp[](~/fundamentals/localization/sample/6.x/Localization/Controllers/AboutController.cs)]
+[!code-csharp[](~/fundamentals/localization/sample/8.x/Localization/Controllers/AboutController.cs)]
 
 In the preceding code, the `IStringLocalizer<T>` implementation comes from [Dependency Injection](~/fundamentals/dependency-injection.md). If the localized value of "About Title" isn't found, then the indexer key is returned, that is, the string "About Title".
 
@@ -35,33 +35,33 @@ Alternatively, you can use the traditional approach and provide a key to retriev
 
 Use the <xref:Microsoft.AspNetCore.Mvc.Localization.IHtmlLocalizer%601> implementation for resources that contain HTML. <xref:Microsoft.AspNetCore.Mvc.Localization.IHtmlLocalizer> HTML-encodes arguments that are formatted in the resource string, but doesn't HTML-encode the resource string itself. In the following highlighted code, only the value of the `name` parameter is HTML-encoded.
 
-[!code-csharp[](~/fundamentals/localization/sample/6.x/Localization/Controllers/BookController.cs?highlight=3,5,20&start=1&end=24)]
+[!code-csharp[](~/fundamentals/localization/sample/8.x/Localization/Controllers/BookController.cs?highlight=3,5,20&start=1&end=24)]
 
 ***NOTE:*** Generally, only localize text, not HTML.
 
 ## `IStringLocalizerFactory`
 
 At the lowest level, <xref:Microsoft.Extensions.Localization.IStringLocalizerFactory> can be retrieved from of [Dependency Injection](~/fundamentals/dependency-injection.md):
 
-[!code-csharp[](~/fundamentals/localization/sample/6.x/Localization/Controllers/TestController.cs?highlight=6-12&name=snippet_1)]
+[!code-csharp[](~/fundamentals/localization/sample/8.x/Localization/Controllers/TestController.cs?highlight=6-12&name=snippet_1)]
 
 The preceding code demonstrates each of the two factory create methods.
 
 ## Shared resources
 
 You can partition your localized strings by controller or area, or have just one container. In the sample app, a marker class named `SharedResource` is used for shared resources. The marker class is never called:
 
-[!code-csharp[](~/fundamentals/localization/sample/6.x/Localization/SharedResource.cs)]
+[!code-csharp[](~/fundamentals/localization/sample/8.x/Localization/SharedResource.cs)]
 
 In the following sample, the `InfoController` and the `SharedResource` localizers are used:
 
-[!code-csharp[](~/fundamentals/localization/sample/6.x/Localization/Controllers/InfoController.cs?name=snippet_1)]
+[!code-csharp[](~/fundamentals/localization/sample/8.x/Localization/Controllers/InfoController.cs?name=snippet_1)]
 
 ## View localization
 
 The <xref:Microsoft.AspNetCore.Mvc.Localization.IViewLocalizer> service provides localized strings for a [view](xref:mvc/views/overview). The `ViewLocalizer` class implements this interface and finds the resource location from the view file path. The following code shows how to use the default implementation of `IViewLocalizer`:
 
-[!code-cshtml[](~/fundamentals/localization/sample/6.x/Localization/Views/Home/About.cshtml)]
+[!code-cshtml[](~/fundamentals/localization/sample/8.x/Localization/Views/Home/About.cshtml)]
 
 The default implementation of `IViewLocalizer` finds the resource file based on the view's file name. There's no option to use a global shared resource file. `ViewLocalizer` implements the localizer using `IHtmlLocalizer`, so Razor doesn't HTML-encode the localized string. You can parameterize resource strings, and `IViewLocalizer` HTML-encodes the parameters but not the resource string. Consider the following Razor markup:
 
@@ -81,7 +81,7 @@ Generally, ***only localize text***, not HTML.
 
 To use a shared resource file in a view, inject `IHtmlLocalizer<T>`:
 
-[!code-cshtml[](~/fundamentals/localization/sample/6.x/Localization/Views/Test/About.cshtml?highlight=5,12)]
+[!code-cshtml[](~/fundamentals/localization/sample/8.x/Localization/Views/Test/About.cshtml?highlight=5,12)]
 
 ## DataAnnotations localization
 
@@ -90,7 +90,7 @@ DataAnnotations error messages are localized with `IStringLocalizer<T>`. Using t
 * *Resources/ViewModels.Account.RegisterViewModel.fr.resx*
 * *Resources/ViewModels/Account/RegisterViewModel.fr.resx*
 
-[!code-csharp[](~/fundamentals/localization/sample/6.x/Localization/ViewModels/Account/RegisterViewModel.cs)]
+[!code-csharp[](~/fundamentals/localization/sample/8.x/Localization/ViewModels/Account/RegisterViewModel.cs)]
 
 Non-validation attributes are localized.
 

aspnetcore/fundamentals/localization/sample/8.x/Localization/Controllers/AboutController.cs

@@ -0,0 +1,21 @@
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.Extensions.Localization;
+
+namespace Localization.Controllers;
+
+[Route("api/[controller]")]
+public class AboutController : Controller
+{
+    private readonly IStringLocalizer<AboutController> _localizer;
+
+    public AboutController(IStringLocalizer<AboutController> localizer)
+    {
+        _localizer = localizer;
+    }
+
+    [HttpGet]
+    public string Get()
+    {
+        return _localizer["About Title"];
+    }
+}