Being Able To Login Using UserName or Email address in ASP.NET Core MVC

Question

I want user to be able to login using UserName or Email in ASP.NET Core MVC. In case of using the [Required] attribute, both the UserName and the Email must be entered in the model properties during login. While doing the form validation on the server-side, I need to perform model validation before accessing the data access layer in the application where the N-Tier architecture is implemented.

namespace LoginApplication.WebUI.Models  
{  
    public class LoginModel  
    {  
        /// <summary>Which data annotation attribute should I use?</summary>  
        public string UserName { get; set; }  
  
        /// <summary>Which data annotation attribute should I use?</summary>  
        public string Email { get; set; }  
  
        [Required]  
        [DataType(DataType.Password)]  
        public string Password { get; set; }  
    }  
}  
  
namespace LoginApplication.WebUI.Controllers  
{  
    public class AccountController : Controller  
    {  
     /* Other LOCs: Dependency Injection, "Login" Action HttpGet Method */  
  
        [HttpPost]  
        public async Task<IActionResult> Login(LoginModel model)  
        {  
            /* At this stage I need to validate the model correctly. */  
            if(ModelState.IsValid)  
            {  
                /* Other LOCs: User Query, Password Authentication, Page Redirection  
                               Error Message Management, Log Management */  
            }  
            return View(model);  
        }  
    }  
}  

In this case, what attribute should I use defined in the System.ComponentModel.DataAnnotations namespace? Or is there another way to work around this situation?

Answer 1

Just allow the user to use their email as username. Trivial with a little javascript and a checkbox.

Answer 2

try this code:
https://stackoverflow.com/questions/7390902/requiredif-conditional-validation-attribute/15975880#15975880

Answer 3

public class SignInViewModel
{
    [Required]

    [Display(Name = "Kullanıcı Adı / Şifre")]
    public string Email { get; set; }


    [Required]
    [DataType(DataType.Password)]
    public string Password { get; set; }

    [Display(Name = "Seni Hatırlayalım mı ?")]
    public bool RememberMe { get; set; }

}

[Route("/giris")]
[Route("/login")]
[HttpPost]
[AllowAnonymous]
[ValidateAntiForgeryToken]
public async Task<IActionResult> Giris(SignInViewModel model, string returnUrl = null)
{
    returnUrl = returnUrl ?? Url.Content("~/");
    if (model.Email.IndexOf('@') > -1)
    {
        //E POSTA DOĞRULAMA  
        string emailRegex = @"^([a-zA-Z0-9_\-\.]+)@((\[[0-9]{1,3}" +
                               @"\.[0-9]{1,3}\.[0-9]{1,3}\.)|(([a-zA-Z0-9\-]+\" +
                                  @".)+))([a-zA-Z]{2,4}|[0-9]{1,3})(\]?)$";
        Regex re = new Regex(emailRegex);
        if (!re.IsMatch(model.Email))
        {
            ModelState.AddModelError("EPosta", "E-Posta doğrulanamadı");
        }
    }
    else
    {
        //KULLANICI ADI DOĞRULAMA
        string emailRegex = @"^[a-zA-Z0-9]*$";
        Regex re = new Regex(emailRegex);
        if (!re.IsMatch(model.Email))
        {
            ModelState.AddModelError("EPosta", "kullanıcı adı doğrulanamadı");
        }
    }

    if (ModelState.IsValid)
    {
        var userName = model.Email;
        if (userName.IndexOf('@') > -1)
        {
            var user = await _userManager.FindByEmailAsync(model.Email);
            if (user == null)
            {
                ModelState.AddModelError("", "değişik bir hata meydana geldi.");
                return View(model);
            }
            else
            {
                userName = user.UserName;
            }
        }
        var result =
            await _signInManager.PasswordSignInAsync(userName, model.Password, model.RememberMe, lockoutOnFailure: true);

hatalı giriş sonucu kullanıcı kilitleme aktif değilse

lockoutOnFailure false yapabilirsiniz.