如何在 asp.net 中将“int”转换为“string”

Question

这是我的登录代码：

public async Task<ActionResult> Login(LoginViewModel model, string returnUrl)
    {
        if (!ModelState.IsValid)
        {
            return View(model);
        }
        var user = UserManager.FindByNameAsync(model.UserName);
       var result = await SignInManager.PasswordSignInAsync(model.UserName, model.Password, model.RememberMe, shouldLockout: false);
        switch (result)
        {
            case SignInStatus.Success:
                if (returnUrl != null)
                    return RedirectToLocal(returnUrl);
                else if (await UserManager.IsInRoleAsync(user.Id, "Admin")) //<= Checking Role and redirecting accordingly.
                    return Redirect("~/Admin/Home/");
                else
                    return Redirect("~/User/Home");
            case SignInStatus.LockedOut:
                return View("Lockout");
            case SignInStatus.RequiresVerification:
                return RedirectToAction("SendCode", new { ReturnUrl = returnUrl, RememberMe = model.RememberMe });
            case SignInStatus.Failure:
            default:
                ModelState.AddModelError("", "Invalid login attempt.");
                return View(model);
        }
    }

但它告诉我这个错误：

论据 1：无法从 'int' 转换为 'string' GoKhoda

在这一行显示错误：

 else if (await UserManager.IsInRoleAsync(user.Id, "Admin"))

此行用于查找用户和用户角色以重定向到页面。

我该如何解决这个问题？

编辑

public class ApplicationUserManager : UserManager<ApplicationUser>
{
    public ApplicationUserManager(IUserStore<ApplicationUser> store)
        : base(store)
    {
    }

    public static ApplicationUserManager Create(IdentityFactoryOptions<ApplicationUserManager> options, IOwinContext context) 
    {
        var manager = new ApplicationUserManager(new UserStore<ApplicationUser>(context.Get<ApplicationDbContext>()));
        // Configure validation logic for usernames
        manager.UserValidator = new UserValidator<ApplicationUser>(manager)
        {
            AllowOnlyAlphanumericUserNames = false,
            RequireUniqueEmail = true
        };

        // Configure validation logic for passwords
        manager.PasswordValidator = new PasswordValidator
        {
            RequiredLength = 6,
            RequireNonLetterOrDigit = true,
            RequireDigit = true,
            RequireLowercase = true,
            RequireUppercase = true,
        };

        // Configure user lockout defaults
        manager.UserLockoutEnabledByDefault = true;
        manager.DefaultAccountLockoutTimeSpan = TimeSpan.FromMinutes(5);
        manager.MaxFailedAccessAttemptsBeforeLockout = 5;

        // Register two factor authentication providers. This application uses Phone and Emails as a step of receiving a code for verifying the user
        // You can write your own provider and plug it in here.
        manager.RegisterTwoFactorProvider("Phone Code", new PhoneNumberTokenProvider<ApplicationUser>
        {
            MessageFormat = "Your security code is {0}"
        });
        manager.RegisterTwoFactorProvider("Email Code", new EmailTokenProvider<ApplicationUser>
        {
            Subject = "Security Code",
            BodyFormat = "Your security code is {0}"
        });
        manager.EmailService = new EmailService();
        manager.SmsService = new SmsService();
        var dataProtectionProvider = options.DataProtectionProvider;
        if (dataProtectionProvider != null)
        {
            manager.UserTokenProvider = 
                new DataProtectorTokenProvider<ApplicationUser>(dataProtectionProvider.Create("ASP.NET Identity"));
        }
        return manager;
    }
}

编辑(2)

当我使用.TosString() 时，显示此错误。

Answer 1

恕我直言，您的错误不仅仅是int 到String 的转换，它与FindByNameAsync 方法有关。当 UserId 属性请求 IsInRoleAsync 方法但 ApplicationUser 类中不存在该属性时会出现问题（与 Dapper 映射问题有关）。

根据MVC - InvalidOperationException: UserId not found，确保FindByNameAsync 像这样在ApplicationUser 中包含Id 属性（如果有，请使用您的EF 数据库上下文而不是查询语句）：

public async Task<ApplicationUser> FindByNameAsync(string userName)
{
    ApplicationUser result = null;
    using (var conn = await GetOpenDBConnection())
    {
        try
        {
            // note that UserId does not exist on ApplicationUser by default
            // thus we need to adjust the query statement
            var queryResults = await conn.QueryAsync<ApplicationUser>(
                "SELECT UserId AS [Id], UserName, Email FROM dbo.Users WHERE UserName = @UserName;",
                new { UserName = userName });

            result = queryResults.FirstOrDefault();
        }
        catch (Exception ex)
        {
            // handle exception
        }
    }
    return result;
}

您也可以尝试FindByName 方法，而不是那里的FindByNameAsync。

关于await 使用错误，异常说明在给定上下文中一次只允许一个异步操作（请参阅Multi-async in Entity Framework 6?），因此您需要将await 移到if 条件之外或创建一个新上下文在执行第二个await之前：

var isInRole = await UserManager.IsInRoleAsync(user.Id.ToString(), "Admin");

// inside switch...case
if (returnUrl != null)
     return RedirectToLocal(returnUrl);
else if (isInRole) //<= Checking Role and redirecting accordingly.
     return Redirect("~/Admin/Home/");
else
     return Redirect("~/User/Home");

如果仍然抛出异常，则更改为IsInRole：

if (returnUrl != null)
    return RedirectToLocal(returnUrl);
else if (UserManager.IsInRole(user.Id.ToString(), "Admin")) //<= Checking Role and redirecting accordingly.
    return Redirect("~/Admin/Home/");
else
    return Redirect("~/User/Home");

这可能会或可能不会解决您的整个问题，但可以解释您应该如何处理与异步相关的问题。

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