Btukfyl

I'm trying to use resource localization in ASP.NET Core MVC 2.1 project to configure validation error messages as described in this article.

I want to separate assemblies in my project in accordance with the onion architecture, to models were in a separate Assembly. Accordingly, the model namespace is different from the host application namespace.
As described here, I call my resource file by the full type name.

However, the messages of the model attributes are not replaced in accordance with the resource files.

What am I doing wrong?

Details:

Model:

using System.ComponentModel.DataAnnotations;



namespace LocalizedAspNetCoreApp.DomainModels

{

    public class TestModel

    {

        [Display(Name = "Value")]

        [Required(ErrorMessage = "ValueRequired")]

        public string Value { get; set; }

    }

}

Sturtup.cs:

using Microsoft.AspNetCore.Builder;

using Microsoft.AspNetCore.Hosting;

using Microsoft.Extensions.Configuration;

using Microsoft.Extensions.DependencyInjection;



namespace LocalizedAspNetCoreApp.Host

{

    public class Startup

    {

        public Startup(IConfiguration configuration)

        {

            Configuration = configuration;

        }



        public IConfiguration Configuration { get; }



        public void ConfigureServices(IServiceCollection services)

        {

            services.AddMvc()

                .AddDataAnnotationsLocalization();

        }



        public void Configure(IApplicationBuilder app, IHostingEnvironment env)

        {

            if (env.IsDevelopment())

            {

                app.UseDeveloperExceptionPage();

            }

            else

            {

                app.UseExceptionHandler("/Home/Error");

            }



            app.UseStaticFiles();



            app.UseMvcWithDefaultRoute();

        }

    }

}

View:

@model TestModel;

@{

    ViewData["Title"] = "About";

}

<h2>@ViewData["Title"]</h2>

<h3>@ViewData["Message"]</h3>



<form method="post" asp-controller="Home" asp-action="About">

    <div asp-validation-summary="ModelOnly"></div>

    <div>

        <label asp-for="Value"></label>

        <input asp-for="Value" />

        <span asp-validation-for="Value"></span>

    </div>

    <div>

        <input type="submit" value="Save" />

    </div>

</form>

Resources

Project structure

Result

First of all:

The path to the resources is determined according to the following template: {RootNamespace}.{ResourceLocation}.{FullTypeName - AssemblyName},
where
{RootNamespace} is, in most cases, the name of the Assembly of the type for which the resource is searched,
{ResourceLocation} - this is usually "Resources",
{FullTypeName - AssemblyName} is the remainder of the type FullName.

You can verify this by injecting the type IStringLocalazer<TestModel> into your controller and accessing the indexer with the key of an existing resource (for example, Value in your case).

The ResourceNotFound property will be set to true and SearchedLocation will reflect the path used to find the resource.

Therefore, model resource files should be placed in the same Assembly where the model is described by the same path pattern:
LocalizedAspNetCoreApp.DomainModels/Resources/TestModel.resx

If the namespace of the type it would be longer than the name of the Assembly, the remaining part should be added to the file name of the resource. For example:
LocalizedAspNetCoreApp.DomainModels/Resources/Models.TestModel.resx

Secondly:

{ResourceLocation} is initialized by default with an empty string.
To initialize this value, install the package Microsoft.Extensions.Localization:

install-package Microsoft.Extensions.Localization

and change ConfigureServices method in Startup.cs:

    public void ConfigureServices(IServiceCollection services)

    {

        services

            .AddLocalization(opts => opts.ResourcesPath = "Resources")

            .AddMvc()

            .AddDataAnnotationsLocalization();

    }