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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 (*****)

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