C# 比较注册表单中存在的用户名，但登录表单也受验证影响

当前的问题是登录页面还比较了exist用户名验证，在登录时提示用户“username exists”。目标是如何从登录页面删除验证，以便只有注册表单具有比较存在用户名验证。对我能做什么有什么建议吗？

对于登录操作，您应该有不同的模型，它只有两个属性用户名和密码，不应该使用元数据属性。对于登录操作，您应该有不同的模型，它只有两个属性用户名和密码，不应该使用元数据属性。

// This is RegisterController  
 public class RegisterController : Controller
{
    AccountEntities db = new AccountEntities();
    // GET: Register
    public ActionResult Register(int id = 0)
    {
        AccountTable accountModel = new AccountTable();
        return View(accountModel);
    }

    [HttpPost]
    public ActionResult Register(AccountTable userModel)
    {

        using (AccountEntities account = new AccountEntities())
        {
            account.AccountTables.Add(userModel);
            account.SaveChanges();
        }
        ModelState.Clear();
        ViewBag.SuccessMessage = "Registration Successful.";
        return View("Register", new AccountTable());
    }

    public JsonResult IsUserExists (string Username)
    {
        return Json(!db.AccountTables.Any(x => x.Username == Username), JsonRequestBehavior.AllowGet);
    }
}

   // this is my modal
   [MetadataType(typeof(UserMetaData))]
public partial class AccountTable
{
    public int UserID { get; set; }

    [DisplayName("User Name")]
    [Required(ErrorMessage = "This field is requried.")]
    [StringLength(10, MinimumLength = 4, ErrorMessage = "length between 4 than 10 characters.")]
    public string Username { get; set; }


    [DataType(DataType.Password)]
    [StringLength(18, MinimumLength = 4, ErrorMessage = "length between 4 than 18 characters.")]
    public string Password { get; set; }


    [DataType(DataType.Password)]
    [DisplayName("Confirm Password")]
    [System.ComponentModel.DataAnnotations.Compare("Password")]
    public string ConfirmPassword { get; set; }



    public string Email { get; set; }


    public string Contact { get; set; }


    public bool isAdmin { get; set; }

    public string LoginErrorMessage { get; set; }

}
public class UserMetaData
{
    [Remote("IsUserExists", "Register", ErrorMessage = "User name already Exists!")]
    public string Username { get; set; }
}


 //this is my login controller
  public class LoginController : Controller
{
    // GET: Login
    public ActionResult Login()
    {
        return View();
    }


    [HttpPost]
    public ActionResult Authourize(theater.Models.AccountTable user)
    {
        using (AccountEntities db = new AccountEntities())
        {
            var userDetails = db.AccountTables.Where(x => x.Username == user.Username && x.Password == user.Password).FirstOrDefault();
            if (userDetails == null)
            {
                user.LoginErrorMessage = "Wrong username or password.";
                return View("Login", user);
            }
            else
            {

                Session["userID"] = userDetails.UserID;
                Session["isAdmin"] = userDetails.isAdmin;
                Session["Username"] = userDetails.Username;

                if (userDetails.isAdmin == true)
                {
                    return RedirectToAction("ControlCenter", "Admin");
                }
                else
                {
                    return RedirectToAction("UserHomePage", "Users");
                }
            }
        }
    }
    public ActionResult LogOut()
    {
        Session.Abandon();
        return RedirectToAction("Login", "Login");
    }
}