Overview

• Internationalization involves Globalization and Localization.
• Globalization is the process of designing apps that support different cultures.
  • Globalization adds support for input, display, and output of a defined set of language scripts that relate to specific geographic areas.
• Localization is the process of adapting a globalized app, which you have already processed for localizability, to a particular culture/locale.
• App localization involves the following:
  1. Make the app's content localizable
  2. Provide localized resources for the languages and cultures you support
  3. Implement a strategy to select the language/culture for each request
• **IStringLocalizer** and **IStringLocalizer<T>** were architected to improve productivity when developing localized apps.
• IStringLocalizer uses the ResourceManager and ResourceReader to provide culture-specific resources at run time.
  • The simple interface has an indexer and an IEnumerable for returning localized strings.
  • IStringLocalizer doesn't require you to store the default language strings in a resource file.
  • You can develop an app targeted for localization and not need to create resource files early in development.
• In the following code, the IStringLocalizer<T> implementation comes from Dependency Injection.
  • If the localized value of "About Title" isn't found, then the indexer key is returned, that is, the string "About Title".
  • You can leave the default language literal strings in the app and wrap them in the localizer, so that you can focus on developing the app.
• You develop your app with your default language and prepare it for the localization step without first creating a default resource file.
  • Alternatively, you can use the traditional approach and provide a key to retrieve the default language string.

[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"];
	}
}

• Use the IHtmlLocalizer<T> implementation for resources that contain HTML.
  • IHtmlLocalizer HTML encodes arguments that are formatted in the resource string, but doesn't HTML encode the resource string itself.

public IActionResult Hello(string name)
{
	ViewData["Message"] = _localizer["<b>Hello</b><i> {0}</i>", name];
	return View();
}

• At the lowest level, you can get IStringLocalizerFactory out of Dependency Injection:

private readonly IStringLocalizer _localizer;
private readonly IStringLocalizer _localizer2;

public TestController(IStringLocalizerFactory factory)
{
	var type = typeof(SharedResource);
	var assemblyName = new AssemblyName(type.GetTypeInfo().Assembly.FullName);
	_localizer = factory.Create(type);
	_localizer2 = factory.Create("SharedResource", assemblyName.Name);
}       

public IActionResult About()
{
	ViewData["Message"] = _localizer["Your application description page."] 
		+ " loc 2: " + _localizer2["Your application description page."];
	// ...
}

• The code above demonstrates each of the two factory create methods.
• You can partition your localized strings by controller, area, or have just one container.
• In the sample app, a dummy class named SharedResource is used for shared resources.

// Dummy class to group shared resources

namespace Localization.StarterWeb
{
    public class SharedResource
    {
    }
}

• Some developers use the Startup class to contain global or shared strings.
• In the sample below, the InfoController and the SharedResource localizers are used: