Default validation message ASP.NET Core

Question

I created custom password validator to check the entering password by using my own regular expression. But when I testing it, the default error message is displayed first, and then mine. And I don't understand how to remove this default message, so that only mine remains. My message is "Your password is incorrect".

Error message:

And there is a code:

Validator:

    {

        public Task<IdentityResult> ValidateAsync(UserManager<User> manager, User user, string password)
        {
            List<IdentityError> errors = new List<IdentityError>();

            string pattern = "^(?=^.{12,}$)(?=.*[0-9]+)(?=.*[A-Z]+)(?=.*[a-z]+)(?=.*[&@^$%]+).*$";

            if (!Regex.IsMatch(password, pattern))
            {
                return Task.FromResult(IdentityResult.Failed(new IdentityError
                {
                    Code = "IncPass",
                    Description = "Your password is incorrect"
                })) ;
            }
            return Task.FromResult(IdentityResult.Success);
        }
    }

Controller methods

 [HttpGet]
        public IActionResult Register()
        {
            return View();
        }
        [HttpPost]
        public async Task<IActionResult> Register(RegisterViewModel model)
        {
            if (ModelState.IsValid)
            {
                User user = new User { Email = model.Email, UserName = model.Email, Year = model.Year };
                var result = await _userManager.CreateAsync(user, model.Password);
                if (result.Succeeded)
                {
                    return RedirectToAction("Index", "Home");
                }
                else
                {
                    foreach (var error in result.Errors)
                    {
                        ModelState.AddModelError(string.Empty, error.Description);
                    }
                }
            }
            return View(model);
        }

Startup

  services.AddIdentity<User, IdentityRole>()
                .AddEntityFrameworkStores<ApplicationContext>()
                .AddDefaultTokenProviders()
                .AddPasswordValidator<CustomPasswordValidator>();

Answer 1

As soon as you call AddIdentity the default password validator is registered, even when you provide a additional password validator.

You need to register your password validator before calling AddIdentity like so:

services.TryAddScoped<IPasswordValidator<User>, CustomPasswordValidator>();
services.AddIdentity<User, IdentityRole>()
            .AddEntityFrameworkStores<ApplicationContext>()
            .AddDefaultTokenProviders();

As you can see, you then don't need the AddPasswordValidator call anymore.

Answer 2

The default PasswordValidator depends on a class called IdentityErrorDescriber .

https://github.com/dotnet/aspnetcore/blob/master/src/Identity/Extensions.Core/src/PasswordValidator.cs

https://docs.microsoft.com/en-us/dotnet/api/microsoft.aspnetcore.identity.identityerrordescriber?view=aspnetcore-3.1

Although it looks possible to override the implementation, it seems this is intended for localization and might be difficult to achieve what you intend.