Skip to main content

Validation ASP.NET Core 2.2 MVC | Login Client-Side Validation

This article will cover adding client-side validation to the ASP.NET Core 2.2. Sometimes we just need a really simple login system for an application. Now I am validating using fields email and password only.

Add validation rules to the Login model:
    public class LoginViewModel
    {
        [Required]
        [EmailAddress]
        [Display(Name = "Email Address")]
        public string Email { get; set; }

        [Required]
        [StringLength(60, MinimumLength = 6)]
        [DataType(DataType.Password)]
        public string Password { get; set; }
    }

The DataAnnotations applied to the class change the schema. The DataAnnotations applied to the Password field.
1.      Passwords must be at least 6 characters.
2.      Limits the characters to 60
3.      Doesn't allow a null value

Validation Error UI in Razor Pages –
@model WebApp.Models.LoginViewModel

<h2>Login</h2>
<form asp-controller="Account" asp-action="Login" method="post">
    <div class="form-group">
        Email:  <input asp-for="Email" /><br />
        <span asp-validation-for="Email" class="text-danger"></span>
    </div>
    <div class="form-group">
        Password: <input asp-for="Password" /><br />
        <span asp-validation-for="Password" class="text-danger"></span>
    </div>
    <div class="form-group">
        <button type="submit">Login</button>
    </div>

    @Html.AntiForgeryToken()
</form>

The Rendered Login form looks like this..

<form method="post" action="/">
    <div class="form-group">
        Email:  <input type="email" data-val="true" data-val-email="The Email Address field is not a valid e-mail address." data-val-required="The Email Address field is required." id="Email" name="Email" value="" /><br />
        <span class="text-danger field-validation-valid" data-valmsg-for="Email" data-valmsg-replace="true"></span>
    </div>
    <div class="form-group">
        Password: <input type="password" data-val="true" data-val-length="The field Password must be a string with a minimum length of 6 and a maximum length of 60." data-val-length-max="60" data-val-length-min="6" data-val-required="The Password field is required." id="Password" maxlength="60" name="Password" /><br />
        <span class="text-danger field-validation-valid" data-valmsg-for="Password" data-valmsg-replace="true"></span>
    </div>
    <div class="form-group">
        <button type="submit">Login</button>
    </div>
</form>

The MVC controller code -
    public class AccountController : Controller
    {

        [HttpPost]
        [ValidateAntiForgeryToken]
        public ActionResult Login(LoginViewModel model)
        {
            try
            {
                if (ModelState.IsValid)
                {
                    //Execute your logic
                }
            }
            catch (Exception ex)
            {
                throw;
            }           
            return View(model);
        }  
    }
Result looks like –


By Anil Singh | Rating of this article (*****)

Popular posts from this blog

nullinjectorerror no provider for httpclient angular 17

In Angular 17 where the standalone true option is set by default, the app.config.ts file is generated in src/app/ and provideHttpClient(). We can be added to the list of providers in app.config.ts Step 1:   To provide HttpClient in a standalone app we could do this in the app.config.ts file, app.config.ts: import { ApplicationConfig } from '@angular/core'; import { provideRouter } from '@angular/router'; import { routes } from './app.routes'; import { provideClientHydration } from '@angular/platform-browser'; //This (provideHttpClient) will help us to resolve the issue  import {provideHttpClient} from '@angular/common/http'; export const appConfig: ApplicationConfig = {   providers: [ provideRouter(routes),  provideClientHydration(), provideHttpClient ()      ] }; The appConfig const is used in the main.ts file, see the code, main.ts : import { bootstrapApplication } from '@angular/platform-browser'; import { appConfig } from '

39 Best Object Oriented JavaScript Interview Questions and Answers

Most Popular 37 Key Questions for JavaScript Interviews. What is Object in JavaScript? What is the Prototype object in JavaScript and how it is used? What is "this"? What is its value? Explain why "self" is needed instead of "this". What is a Closure and why are they so useful to us? Explain how to write class methods vs. instance methods. Can you explain the difference between == and ===? Can you explain the difference between call and apply? Explain why Asynchronous code is important in JavaScript? Can you please tell me a story about JavaScript performance problems? Tell me your JavaScript Naming Convention? How do you define a class and its constructor? What is Hoisted in JavaScript? What is function overloadin

25 Best Vue.js 2 Interview Questions and Answers

What Is Vue.js? The Vue.js is a progressive JavaScript framework and used to building the interactive user interfaces and also it’s focused on the view layer only (front end). The Vue.js is easy to integrate with other libraries and others existing projects. Vue.js is very popular for Single Page Applications developments. The Vue.js is lighter, smaller in size and so faster. It also supports the MVVM ( Model-View-ViewModel ) pattern. The Vue.js is supporting to multiple Components and libraries like - ü   Tables and data grids ü   Notifications ü   Loader ü   Calendar ü   Display time, date and age ü   Progress Bar ü   Tooltip ü   Overlay ü   Icons ü   Menu ü   Charts ü   Map ü   Pdf viewer ü   And so on The Vue.js was developed by “ Evan You ”, an Ex Google software engineer. The latest version is Vue.js 2. The Vue.js 2 is very similar to Angular because Evan You was inspired by Angular and the Vue.js 2 components looks like -

55 Best TypeScript Interview Questions and Answers - JavaScript!

What Is TypeScript? By definition, "TypeScript is a typed superset of JavaScript that compiles to plain JavaScript." TypeScript is a superset of JavaScript which provides optional static typing, classes and interfaces. => The TypeScript was first made public in the year 2012. => Typescript is a modern age JavaScript development language. => TypeScript is a strongly typed, object oriented, compiled language. => TypeScript was designed by Anders Hejlsberg (designer of C#) at Microsoft. => TypeScript is both a language and a set of tools. As an Example of TypeScript, class Hello {     msg : string ;      constructor ( message : string ) {          this . msg = message ;      }       getMsg () {          return "Hello, " + this . msg ;      } } TypeScript introduced a great deal of syntax taken from object-oriented programming, including but not limited to: 1) Interfaces 2) Classes 3) Enumerated t

List of Countries, Nationalities and their Code In Excel File

Download JSON file for this List - Click on JSON file    Countries List, Nationalities and Code Excel ID Country Country Code Nationality Person 1 UNITED KINGDOM GB British a Briton 2 ARGENTINA AR Argentinian an Argentinian 3 AUSTRALIA AU Australian an Australian 4 BAHAMAS BS Bahamian a Bahamian 5 BELGIUM BE Belgian a Belgian 6 BRAZIL BR Brazilian a Brazilian 7 CANADA CA Canadian a Canadian 8 CHINA CN Chinese a Chinese 9 COLOMBIA CO Colombian a Colombian 10 CUBA CU Cuban a Cuban 11 DOMINICAN REPUBLIC DO Dominican a Dominican 12 ECUADOR EC Ecuadorean an Ecuadorean 13 EL SALVADOR