我是编程新手，我的程序没有任何错误，但我的登录不起作用，当我输入密码和用户名并单击按钮时，它不会进入管理页面 - 它实际上并没有去任何地方并返回登录页面（本身）。

我的管理操作方法具有 [Authorize] 属性，并且我认为数据库中的一切正常，并且数据插入带有种子数据。请帮忙。

startup.cs

public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{
    app.UseStatusCodePagesWithRedirects("/Home/Error");
    app.UseStaticFiles();
    app.UseRouting();
    app.UseAuthentication();
    app.UseAuthorization();

    app.UseEndpoints(endpoints =>
        {
            endpoints.MapControllerRoute(
                name: "default",
                pattern: "{controller=Home}/{action=Index}/{id?}");
        });
}

AccountController.cs

public IActionResult Login()
{
    return View();
}

[HttpPost]
public IActionResult Login(Admin login, FormCollection form)
{
    if (ModelState.IsValid)
    {
        var user = loginRepository.IsExistUser(login.UserName, login.Password);

        if (user != "")
        {
            return Redirect("/Home/Admin");
        }
        else
        {
            ModelState.AddModelError("UserName", "there is no user");
        }
    }

    var claims = new List
        {
            new Claim(ClaimTypes.NameIdentifier,login.LoginID.ToString()),
            new Claim(ClaimTypes.Name,login.UserName),
            new Claim(ClaimTypes.Name,login.Password),
        };

    var Identity = new ClaimsIdentity(claims, `enter code here`CookieAuthenticationDefaults.AuthenticationScheme);
    var principal = new ClaimsPrincipal(Identity);

    var properties = new AuthenticationProperties
        {
            IsPersistent = login.RememberMe
        };

    HttpContext.SignInAsync(principal, properties);

    //********recaptcha * ********
    string urlToPost = "https://www.google.com/recaptcha/api/siteverify";
    string secretKey = "";
    string gRecaptchaResponse = form["g-recaptcha-response"];

    var postData = "secret=" + secretKey + "&response=" + gRecaptchaResponse;

    // send post data
    HttpWebRequest request = (HttpWebRequest)WebRequest.Create(urlToPost);
    request.Method = "POST";
    request.ContentLength = postData.Length;
    request.ContentType = "application/x-www-form-urlencoded";

    using (var streamWriter = new StreamWriter(request.GetRequestStream()))
    {
        streamWriter.Write(postData);
    }

    // receive the response now
    string result = string.Empty;

    using (HttpWebResponse response = (HttpWebResponse)request.GetResponse())
    {
        using (var reader = new StreamReader(response.GetResponseStream()))
        {
            result = reader.ReadToEnd();
        }
    }

    ViewBag.IsSuccess = false;

    return View("login");
}

public IActionResult Lougout()
{
    HttpContext.SignOutAsync(CookieAuthenticationDefaults.AuthenticationScheme);
    return Redirect("/Account/Login");
}

LoginRepository.cs

public string IsExistUser(string username, string password)
{
    return db.Admin.SingleOrDefault(u => u.UserName == username && u.Password == password).ToString();
}

ILoginRepository.cs

string IsExistUser(string username, string password);

login.cshtml

@model DataLayer.Admin

@{
    ViewData["LoginTitle"] = "sign in";
    Layout = "/Views/Shared/_LoginLayout.cshtml";
}



    

        

            

                
                
                username:
                
            
        

        

            

                
                
                password:
                
            
        

        

            

                
                
            
        
        

            
        

        

            go to form
        
    




@section Scripts {
    @{await Html.RenderPartialAsync("_ValidationScriptsPartial");}
}

model.cs

using System.ComponentModel.DataAnnotations;

namespace DataLayer
{
    public class Admin
    {
        [Key]
        public int LoginID { get; set; }

        [Display(Name = "username")]
        [Required(ErrorMessage = "please enter your username")]
        [MaxLength(20)]
        public string UserName { get; set; }


        [Display(Name = "password")]
        [Required(ErrorMessage = "please enter your password")]
        [MaxLength(20)]
        [DataType(DataType.Password)]
        public string Password { get; set; }


        [Display(Name = "remember me")]
        public bool RememberMe { get; set; }
    }
}

HomeController

        [Authorize]
        public IActionResult Admin()
        {
            return View();
        }

而且我的模型验证也不起作用（输入中的 asp-validation-for ） - 我不知道为什么。