Globalization and Localization of Model Validation Messages in ASP.NET MVC

On the Visual Studio, create new ASP.NET MVC Web Application project

Select Empty Template and Core Reference is MVC

Create App_GlobalResources folder in project. Create new resource file named ErrorMessages.resx contains error messages as photo below. Copy this file and translate to languages need display: ErrorMessages.en.resx, ErrorMessages.fr.resx and ErrorMessages.de.resx

Open Global.asax file and set English is default locale for display error messages as below:

using System;
using System.Collections.Generic;
using System.Globalization;
using System.Linq;
using System.Threading;
using System.Web;
using System.Web.Mvc;
using System.Web.Routing;

namespace LearnASPNETMVCWithRealApps
{
    public class MvcApplication : System.Web.HttpApplication
    {
        protected void Application_Start()
        {
            AreaRegistration.RegisterAllAreas();
            RouteConfig.RegisterRoutes(RouteTable.Routes);
        }

        protected void Application_AcquireRequestState(object sender, EventArgs e)
        {
            HttpContext context = HttpContext.Current;
            var languageSession = "en";
            Thread.CurrentThread.CurrentUICulture = new CultureInfo(languageSession);
            Thread.CurrentThread.CurrentCulture = new CultureInfo(languageSession);
        }

    }
}

In Models folder, create new entities class as below:

Create new class named Account.cs as below:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.ComponentModel.DataAnnotations;

namespace LearnASPNETMVCWithRealApps.Models
{
    public class Account
    {
        [Required(ErrorMessageResourceType = typeof(Resources.ErrorMessages), ErrorMessageResourceName = "Required")]
        [MinLength(3, ErrorMessageResourceType = typeof(Resources.ErrorMessages), ErrorMessageResourceName = "MinLength")]
        [MaxLength(10, ErrorMessageResourceType = typeof(Resources.ErrorMessages), ErrorMessageResourceName = "MaxLength")]
        [Display(Name = "Username")]
        public string Username
        {
            get;
            set;
        }

        [Required(ErrorMessageResourceType = typeof(Resources.ErrorMessages), ErrorMessageResourceName = "Required")]
        [MinLength(3, ErrorMessageResourceType = typeof(Resources.ErrorMessages), ErrorMessageResourceName = "MinLength")]
        [MaxLength(10, ErrorMessageResourceType = typeof(Resources.ErrorMessages), ErrorMessageResourceName = "MaxLength")]
        [RegularExpression("((?=.*\\d)(?=.*[a-z])(?=.*[A-Z])(?=.*[@#$%]).{6,20})", ErrorMessageResourceType = typeof(Resources.ErrorMessages), ErrorMessageResourceName = "RegularExpression")]
        public string Password
        {
            get;
            set;
        }

        [Required(ErrorMessageResourceType = typeof(Resources.ErrorMessages), ErrorMessageResourceName = "Required")]
        public string FullName
        {
            get;
            set;
        }

        [Required(ErrorMessageResourceType = typeof(Resources.ErrorMessages), ErrorMessageResourceName = "Required")]
        [Range(18, 50, ErrorMessageResourceType = typeof(Resources.ErrorMessages), ErrorMessageResourceName = "Range")]
        public int Age
        {
            get;
            set;
        }

        [Required(ErrorMessageResourceType = typeof(Resources.ErrorMessages), ErrorMessageResourceName = "Required")]
        [EmailAddress(ErrorMessageResourceType = typeof(Resources.ErrorMessages), ErrorMessageResourceName = "EmailAddress")]
        public string Email
        {
            get;
            set;
        }

        [Url(ErrorMessageResourceType = typeof(Resources.ErrorMessages), ErrorMessageResourceName = "Url")]
        public string Website
        {
            get;
            set;
        }

    }
}

In Controllers folder, create new controller named AccountController.cs as below:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;
using LearnASPNETMVCWithRealApps.Models;

namespace LearnASPNETMVCWithRealApps.Controllers
{
    public class AccountController : Controller
    {
        [HttpGet]
        public ActionResult Index()
        {
            return View();
        }

        [HttpPost]
        public ActionResult Index(Account account)
        {
            // Custom validation
            if (account.Username != null && account.Username.Equals("abc123"))
            {
                ModelState.AddModelError("Username", Resources.ErrorMessages.UsernameAlready);
            }
            if (ModelState.IsValid)
            {
                ViewBag.account = account;
                return View("Success");
            }
            return View("Index");
        }

    }
}

In Views/Account folder, create new razor views as below:

Create new view named Index.cshtml as below:

@{
    Layout = null;
}

@model LearnASPNETMVCWithRealApps.Models.Account

<!DOCTYPE html>

<html>
<head>
    <meta name="viewport" content="width=device-width" />
    <title>Index</title>
</head>
<body>

    <h3>Account Register</h3>
    @using (Html.BeginForm("Index", "Account"))
    {
        <table cellpadding="2" cellspacing="2" border="0">
            <tr>
                <td>Username</td>
                <td>@Html.TextBoxFor(model => model.Username)</td>
                <td>@Html.ValidationMessageFor(model => model.Username)</td>
            </tr>
            <tr>
                <td>Password</td>
                <td>@Html.PasswordFor(model => model.Password)</td>
                <td>@Html.ValidationMessageFor(model => model.Password)</td>
            </tr>
            <tr>
                <td>Full Name</td>
                <td>@Html.TextBoxFor(model => model.FullName)</td>
                <td>@Html.ValidationMessageFor(model => model.FullName)</td>
            </tr>
            <tr>
                <td>Age</td>
                <td>@Html.TextBoxFor(model => model.Age)</td>
                <td>@Html.ValidationMessageFor(model => model.Age)</td>
            </tr>
            <tr>
                <td>Email</td>
                <td>@Html.TextBoxFor(model => model.Email)</td>
                <td>@Html.ValidationMessageFor(model => model.Email)</td>
            </tr>
            <tr>
                <td>Website</td>
                <td>@Html.TextBoxFor(model => model.Website)</td>
                <td>@Html.ValidationMessageFor(model => model.Website)</td>
            </tr>
            <tr>
                <td>&nbsp;</td>
                <td colspan="2"><input type="submit" value="Save" /></td>
            </tr>
        </table>
    }

</body>
</html>

Create new view named Success.cshtml as below:

@{
    Layout = null;
}

<!DOCTYPE html>

<html>
<head>
    <meta name="viewport" content="width=device-width" />
    <title>Success</title>
</head>
<body>

    <h3>Account Info</h3>
    <table cellpadding="2" cellspacing="2" border="1">
        <tr>
            <td>Username</td>
            <td>@ViewBag.account.Username</td>
        </tr>
        <tr>
            <td>Password</td>
            <td>@ViewBag.account.Password</td>
        </tr>
        <tr>
            <td>Full Name</td>
            <td>@ViewBag.account.FullName</td>
        </tr>
        <tr>
            <td>Age</td>
            <td>@ViewBag.account.Age</td>
        </tr>
        <tr>
            <td>Email</td>
            <td>@ViewBag.account.Email</td>
        </tr>
        <tr>
            <td>Website</td>
            <td>@ViewBag.account.Website</td>
        </tr>
    </table>
</body>
</html>

Access Index action in Account controller with following url: http://localhost:9596/Account/Index

Output

Click Save button submit form to Save action in Account controller with some instances of invalid data as below:

Case 1

Case 2

Click Save button submit form to Save action in Account controller with valid data

Output

I recommend you refer to the books below to learn more about the knowledge in this article:

Globalization and Localization of Model Validation Messages in ASP.NET MVC

Create ASP.NET MVC Project

Resource Files

Set Default Locale

Entities Class

Account Entity

Create Controller

Create View

Index View

Success View

Structure of ASP.NET MVC Project

Run Application

References