InvalidCastException：无法将“System.String”类型的对象转换为“System.Guid”类型。 ASP.NET

Question

我有一个网络应用程序，基本上一切正常。今天，我想用 ApplicationUser 扩展我的 IdentityUser，以便用户可以拥有 FirstName、LastName 和 ProfilePicture。 问题就来了。当我向应用程序用户注册用户时，一切正常，并且用户已在数据库中登录。但是，当我尝试访问帐户/管理或帐户/登录时，会弹出以下错误：

我正在发布我的 applicationUser 类、我的登录、注册和管理视图和 cs.html

namespace OnlineShop.Data.Models
{
    public class ApplicationUser : IdentityUser<Guid>
    {
        public string? FirstName { get; set; }
        public string? LastName { get; set; }
        public string? ProfileImgUrl { get; set; }
    }
}

应用程序DbContext：

namespace OnlineShop.Data
{
    public class ApplicationDbContext : IdentityDbContext<ApplicationUser, IdentityRole<Guid>, Guid>
    {
        public ApplicationDbContext()
        {

        }
        public ApplicationDbContext(DbContextOptions<ApplicationDbContext> options)
            : base(options)
        {
        }

        public DbSet<Payment> Payments { get; set; }
        public DbSet<Order> Orders { get; set; }
        public DbSet<OrderProduct> OrdersProducts { get; set; }
        public DbSet<Product> Products { get; set; }
        public DbSet<ShoppingCart> ShoppingCarts { get; set; }
        public DbSet<ShoppingCartProduct> ShoppingCartsProducts { get; set; }
        public DbSet<Gender> Genders { get; set; }
        public DbSet<ClothingType> ClothingTypes { get; set; }
        public DbSet<Review> Reviews { get; set; }

        protected override void OnModelCreating(ModelBuilder modelBuilder)
        {
            modelBuilder.ApplyConfigurationsFromAssembly(Assembly.GetExecutingAssembly());
            base.OnModelCreating(modelBuilder);
        }
    }
}

程序.cs

builder.Services.AddDefaultIdentity<ApplicationUser>(options =>
{
    options.SignIn.RequireConfirmedAccount = false;
    options.Password.RequireNonAlphanumeric = false;
}).AddRoles<IdentityRole<Guid>>()
    .AddEntityFrameworkStores<ApplicationDbContext>();

注册.cshtml.cs

// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
#nullable disable

namespace OnlineShop.Web.Areas.Identity.Pages.Account
{
    public class RegisterModel : PageModel
    {
        private readonly SignInManager<ApplicationUser> _signInManager;
        private readonly UserManager<ApplicationUser> _userManager;
        private readonly IUserStore<ApplicationUser> _userStore;
        private readonly IUserEmailStore<ApplicationUser> _emailStore;
        private readonly ILogger<RegisterModel> _logger;
        private readonly IEmailSender _emailSender;

        public RegisterModel(
            UserManager<ApplicationUser> userManager,
            IUserStore<ApplicationUser> userStore,
            SignInManager<ApplicationUser> signInManager,
            ILogger<RegisterModel> logger,
            IEmailSender emailSender)
        {
            _userManager = userManager;
            _userStore = userStore;
            _emailStore = GetEmailStore();
            _signInManager = signInManager;
            _logger = logger;
            _emailSender = emailSender;
        }

        /// <summary>
        ///     This API supports the ASP.NET Core Identity default UI infrastructure and is not intended to be used
        ///     directly from your code. This API may change or be removed in future releases.
        /// </summary>
        [BindProperty]
        public InputModel Input { get; set; }

        /// <summary>
        ///     This API supports the ASP.NET Core Identity default UI infrastructure and is not intended to be used
        ///     directly from your code. This API may change or be removed in future releases.
        /// </summary>
        public string ReturnUrl { get; set; }

        /// <summary>
        ///     This API supports the ASP.NET Core Identity default UI infrastructure and is not intended to be used
        ///     directly from your code. This API may change or be removed in future releases.
        /// </summary>
        public IList<AuthenticationScheme> ExternalLogins { get; set; }

        /// <summary>
        ///     This API supports the ASP.NET Core Identity default UI infrastructure and is not intended to be used
        ///     directly from your code. This API may change or be removed in future releases.
        /// </summary>
        public class InputModel
        {
            public string FirstName { get; set; }
            public string LastName { get; set; }
            public string ProfileImgUrl { get; set; }
            /// <summary>
            ///     This API supports the ASP.NET Core Identity default UI infrastructure and is not intended to be used
            ///     directly from your code. This API may change or be removed in future releases.
            /// </summary>
            [Required]
            [EmailAddress]
            [Display(Name = "Email")]
            public string Email { get; set; }

            /// <summary>
            ///     This API supports the ASP.NET Core Identity default UI infrastructure and is not intended to be used
            ///     directly from your code. This API may change or be removed in future releases.
            /// </summary>
            [Required]
            [StringLength(100, ErrorMessage = "The {0} must be at least {2} and at max {1} characters long.", MinimumLength = 6)]
            [DataType(DataType.Password)]
            [Display(Name = "Password")]
            public string Password { get; set; }

            /// <summary>
            ///     This API supports the ASP.NET Core Identity default UI infrastructure and is not intended to be used
            ///     directly from your code. This API may change or be removed in future releases.
            /// </summary>
            [DataType(DataType.Password)]
            [Display(Name = "Confirm password")]
            [Compare("Password", ErrorMessage = "The password and confirmation password do not match.")]
            public string ConfirmPassword { get; set; }
        }


        public async Task OnGetAsync(string returnUrl = null)
        {
            ReturnUrl = returnUrl;
            ExternalLogins = (await _signInManager.GetExternalAuthenticationSchemesAsync()).ToList();
        }

        public async Task<IActionResult> OnPostAsync(string returnUrl = null)
        {
            returnUrl ??= Url.Content("~/");
            ExternalLogins = (await _signInManager.GetExternalAuthenticationSchemesAsync()).ToList();
            if (ModelState.IsValid)
            {
                var user = CreateUser();

                user.FirstName = Input.FirstName;
                user.LastName = Input.LastName;
                user.ProfileImgUrl = Input.ProfileImgUrl;

                await _userStore.SetUserNameAsync(user, Input.Email, CancellationToken.None);
                await _emailStore.SetEmailAsync(user, Input.Email, CancellationToken.None);
                var result = await _userManager.CreateAsync(user, Input.Password);

                if (result.Succeeded)
                {
                    _logger.LogInformation("User created a new account with password.");

                    var userId = await _userManager.GetUserIdAsync(user);
                    var code = await _userManager.GenerateEmailConfirmationTokenAsync(user);
                    code = WebEncoders.Base64UrlEncode(Encoding.UTF8.GetBytes(code));
                    var callbackUrl = Url.Page(
                        "/Account/ConfirmEmail",
                        pageHandler: null,
                        values: new { area = "Identity", userId = userId, code = code, returnUrl = returnUrl },
                        protocol: Request.Scheme);

                    await _emailSender.SendEmailAsync(Input.Email, "Confirm your email",
                        $"Please confirm your account by <a href='{HtmlEncoder.Default.Encode(callbackUrl)}'>clicking here</a>.");

                    if (_userManager.Options.SignIn.RequireConfirmedAccount)
                    {
                        return RedirectToPage("RegisterConfirmation", new { email = Input.Email, returnUrl = returnUrl });
                    }
                    else
                    {
                        await _signInManager.SignInAsync(user, isPersistent: false);
                        return LocalRedirect(returnUrl);
                    }
                }
                foreach (var error in result.Errors)
                {
                    ModelState.AddModelError(string.Empty, error.Description);
                }
            }

            // If we got this far, something failed, redisplay form
            return Page();
        }

        private ApplicationUser CreateUser()
        {
            try
            {
                return Activator.CreateInstance<ApplicationUser>();
            }
            catch
            {
                throw new InvalidOperationException($"Can't create an instance of '{nameof(IdentityUser)}'. " +
                    $"Ensure that '{nameof(IdentityUser)}' is not an abstract class and has a parameterless constructor, or alternatively " +
                    $"override the register page in /Areas/Identity/Pages/Account/Register.cshtml");
   

     }
    }

    private IUserEmailStore<ApplicationUser> GetEmailStore()
    {
        if (!_userManager.SupportsUserEmail)
        {
            throw new NotSupportedException("The default UI requires a user store with email support.");
        }
        return (IUserEmailStore<ApplicationUser>)_userStore;
    }
}

}

登录.cshtml.cs

// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
#nullable disable

namespace OnlineShop.Web.Areas.Identity.Pages.Account
{
    public class LoginModel : PageModel
    {
        private readonly SignInManager<ApplicationUser> _signInManager;
        private readonly UserManager<ApplicationUser> _userManager;
        private readonly ILogger<LoginModel> _logger;

        public LoginModel(SignInManager<ApplicationUser> signInManager, UserManager<ApplicationUser> userManager, ILogger<LoginModel> logger)
        {
            _signInManager = signInManager;
            _userManager = userManager;
            _logger = logger;
        }

        [BindProperty]
        public InputModel Input { get; set; }

        public IList<AuthenticationScheme> ExternalLogins { get; set; }

        public string ReturnUrl { get; set; }

        [TempData]
        public string ErrorMessage { get; set; }

        public class InputModel
        {
            [Required]
            [EmailAddress]
            public string Email { get; set; }

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

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

        public async Task OnGetAsync(string returnUrl = null)
        {
            if (!string.IsNullOrEmpty(ErrorMessage))
            {
                ModelState.AddModelError(string.Empty, ErrorMessage);
            }

            returnUrl ??= Url.Content("~/");

            // Clear the existing external cookie to ensure a clean login process
            await HttpContext.SignOutAsync(IdentityConstants.ExternalScheme);

            ExternalLogins = (await _signInManager.GetExternalAuthenticationSchemesAsync()).ToList();

            ReturnUrl = returnUrl;
        }

        public async Task<IActionResult> OnPostAsync(string returnUrl = null)
        {
            returnUrl ??= Url.Content("~/");

            ExternalLogins = (await _signInManager.GetExternalAuthenticationSchemesAsync()).ToList();

            if (ModelState.IsValid)
            {
                // Log the attempted email to help with debugging
                _logger.LogInformation("Attempting to sign in user with email: {Email}", Input.Email);

                // Lookup user by email
                var userEmail = Input.Email;
                var user = await _userManager.FindByNameAsync(userEmail);
                if (user == null)
                {
                    _logger.LogWarning("User not found for email: {Email}", Input.Email);
                }

                // This doesn't count login failures towards account lockout
                // To enable password failures to trigger account lockout, set lockoutOnFailure: true
                var result = await _signInManager.PasswordSignInAsync(Input.Email, Input.Password, Input.RememberMe, lockoutOnFailure: false);

                if (result.Succeeded)
                {
                    _logger.LogInformation("User logged in.");
                    return LocalRedirect(returnUrl);
                }
                if (result.RequiresTwoFactor)
                {
                    return RedirectToPage("./LoginWith2fa", new { ReturnUrl = returnUrl, RememberMe = Input.RememberMe });
                }
                if (result.IsLockedOut)
                {
                    _logger.LogWarning("User account locked out.");
                    return RedirectToPage("./Lockout");
                }
                else
                {
                    ModelState.AddModelError(string.Empty, "Invalid login attempt.");
                    return Page();
                }
            }

            // If we got this far, something failed, redisplay form
            return Page();
        }
    }
}

Answer 1

根据你的代码，我创建了一个新的Razor页面应用程序并像你一样自定义Identity User，使用迁移命令生成数据库后，

AspNetUsers

的主键和

AspNetRoles

表主键id

 uniqueidentifier

数据类型（SQL Server），然后我检查了你的注册和登录代码，它们都运行良好并且无法重现问题。

InvalidCastException：无法将“System.String”类型的对象转换为 输入“System.Guid”。

当应用程序的身份模型中定义的数据类型与数据库中存储的数据类型不匹配时，ASP.NET Core Identity 中通常会出现此错误。

public class ApplicationUser : IdentityUser<Guid>

and

public class ApplicationDbContext : IdentityDbContext<ApplicationUser, IdentityRole<Guid>, Guid>
{

从上面的代码中，我们可以看到您已经自定义了身份模型，使用

Guid

作为主键。然后，迁移成功后，检查数据库中的表定义，我们可以看到

AspNetUsers

表应该具有

Id

列，如

uniqueidentifier

（SQL Server）或其他数据库中

Guid

的等效类型。

所以，请检查数据库中您的数据表定义。

在数据库中，如果仍然使用

nvarchar

数据类型（默认），可能是您在自定义身份用户后忘记启用迁移。然后，

要解决此问题，您需要生成并应用新的迁移（使用 add-migration XXX

 和 

update-database

 命令）以在数据库中反映此更改，确保数据类型匹配

。

[注意] 启用迁移时，您可能会遇到“对象‘PK_AspNetUserTokens’依赖于列‘UserId’”错误，要解决此问题，您可以删除文件夹“Migration”并重新添加迁移。请参阅此线程。

此外，您还可以尝试删除现有数据库并删除“Migration”文件夹并再次添加迁移，然后您的代码应该可以在新数据库上运行。