Globalization (G11N): The process of making an app support different languages and regions.

Localization (L10N): The process of customizing a globalized app for specific languages and regions

Step 1: Make the App's Content Localizable

Purpose:

To allow the app to support different languages by externalizing user-facing strings into resource files.

Actions:

• Enable localization services in the app.
• Add resx resource files to store localized strings.
• Decide where to place resource files: in the same project (Presentation Layer) or a shared project (e.g., Project.Shared).
• AddViewLocalization(...) enables localized Razor Views (e.g., Index.ar.cshtml).
• AddDataAnnotationsLocalization() enables localization of [Display], [Required], and other attributes.

🔹 Path 1: Resource Files in the Same Project (Simple Case)

Sample Code (Program.cs):

var builder = WebApplication.CreateBuilder(args);

builder.Services.AddLocalization(options => options.ResourcesPath = "Resources");

builder.Services.AddControllersWithViews()
.AddViewLocalization(LanguageViewLocationExpanderFormat.Suffix)
.AddDataAnnotationsLocalization();

// example for using localization with data annotation
 public class ProductDTO
 {
     public Guid? Id { get; set; }

     [Required(ErrorMessageResourceType = typeof(SharedResource), ErrorMessageResourceName = "ProductNameRequired")]
     [StringLength(100, ErrorMessageResourceType = typeof(SharedResource), ErrorMessageResourceName = "ProductNameMaxLength")]
     public string Name { get; set; }

     [StringLength(500, ErrorMessageResourceType = typeof(SharedResource), ErrorMessageResourceName = "DescriptionMaxLength")]
     public string Description { get; set; }

     [Required(ErrorMessageResourceType = typeof(SharedResource), ErrorMessageResourceName = "PriceRequired")]
     [Range(0.01, 1000000, ErrorMessageResourceType = typeof(SharedResource), ErrorMessageResourceName = "PriceRange")]
     public double Price { get; set; }
 }

Explanation:

• AddLocalization: Registers the localization services. (IStringLocalizaer, IHtmlLocalizer, IViewLocalizer, IStringLocalizerFactory)
• ResourcesPath = "Resources": Looks for .resx files in the /Resources folder inside the Presentation layer.
• What is LanguageViewLocationExpanderFormat.Suffix?
  • It's an enum value used in this method: The Suffix option tells ASP.NET Core to look for culture-specific views by appending the culture name as a suffix to the view file name.