System.InvalidOperationException：Scheme 已经存在：Identity.Application：Identity Scaffolding 之后

Question

我有一个现有的ApplicationUser，我想修改登录的 UI 页面。所以这就是我决定执行脚手架操作的原因。

ApplicationUser.cs

public class ApplicationUser : IdentityUser
{
    public List<Student> Students { get; set; }
}

但是当我使用最后一个CLI 命令时：

dotnet aspnet-codegenerator identity --files="Account.Login;"

我无法运行我的网络应用程序，这是它在网络上显示的内容：

然后，这是日志中发生的错误：

未处理的异常：System.InvalidOperationException：Scheme 已经 存在：Identity.Application 在 Microsoft.AspNetCore.Authentication.AuthenticationOptions.AddScheme（字符串 名称，Action1 configureBuilder) at Microsoft.AspNetCore.Authentication.AuthenticationBuilder.<>c__DisplayClass4_02.b__0(AuthenticationOptions o) 在 Microsoft.Extensions.Options.ConfigureNamedOptions1.Configure(String name, TOptions options) at Microsoft.Extensions.Options.OptionsFactory1.Create(字符串名称)
在 Microsoft.Extensions.Options.OptionsManager1.<>c__DisplayClass5_0.<Get>b__0() at System.Lazy1.ViaFactory（LazyThreadSafetyMode 模式）在 System.Lazy1.ExecutionAndPublication(LazyHelper executionAndPublication, Boolean useDefaultConstructor) at System.Lazy1.CreateValue() 在 Microsoft.Extensions.Options.OptionsCache1.GetOrAdd(String name, Func1 createOptions) 在 Microsoft.Extensions.Options.OptionsManager1.Get(String name) at Microsoft.Extensions.Options.OptionsManager1.get_Value() 在 Microsoft.AspNetCore.Authentication.AuthenticationSchemeProvider..ctor(IOptions1 options, IDictionary2 方案) 在 Microsoft.AspNetCore.Authentication.AuthenticationSchemeProvider..ctor(IOptions1 options) --- End of stack trace from previous location where exception was thrown --- at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitConstructor(ConstructorCallSite constructorCallSite, ServiceProviderEngineScope scope) at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor2.VisitCallSite(IServiceCallSite callSite, TArgument 参数）在 Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitScoped（ScopedCallSite scopedCallSite、ServiceProviderEngineScope 范围）在 Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitSingleton(SingletonCallSite singletonCallSite，ServiceProviderEngineScope 范围）在 Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2.VisitCallSite(IServiceCallSite callSite, TArgument 参数）在 Microsoft.Extensions.DependencyInjection.ServiceLookup.DynamicServiceProviderEngine.c__DisplayClass1_0.b__0(ServiceProviderEngineScope 范围）在 Microsoft.Extensions.DependencyInjection.ServiceLookup.ServiceProviderEngine.GetService（类型 serviceType, ServiceProviderEngineScope serviceProviderEngineScope)
在 Microsoft.Extensions.DependencyInjection.ServiceLookup.ServiceProviderEngine.GetService（类型 服务类型）在 Microsoft.Extensions.DependencyInjection.ServiceProvider.GetService（类型 服务类型）在 Microsoft.Extensions.Internal.ActivatorUtilities.ConstructorMatcher.CreateInstance（IServiceProvider 提供者）在 Microsoft.Extensions.Internal.ActivatorUtilities.CreateInstance（IServiceProvider 提供者，类型 instanceType，Object[] 参数）在 Microsoft.AspNetCore.Builder.UseMiddlewareExtensions.c__DisplayClass4_0.b__0(RequestDelegate 下一个）在 Microsoft.AspNetCore.Builder.Internal.ApplicationBuilder.Build() 在 Microsoft.AspNetCore.Hosting.Internal.WebHost.BuildApplication() 在 Microsoft.AspNetCore.Hosting.Internal.WebHost.StartAsync（CancellationToken 取消令牌）在 Microsoft.AspNetCore.Hosting.WebHostExtensions.RunAsync（IWebHost 主机， CancellationToken 令牌，字符串 shutdownMessage）在 Microsoft.AspNetCore.Hosting.WebHostExtensions.RunAsync（IWebHost 主机， CancellationToken 令牌）在 Microsoft.AspNetCore.Hosting.WebHostExtensions.Run(IWebHost 主机)
在 ICFERApp.Program.Main(String[] args) 中 /Users/idrislutaaya/RiderProjects/ICFERApp/ICFERApp/Program.cs:第 17 行

我看过这个question，但没有帮助。

其实让我吃惊的是，有一个 DBClass 在这个目录 ~/Areas/Identity/Data 中创建了它自己，如下：

public class ICFERAppIdentityDbContext : IdentityDbContext<IdentityUser>
{
    public ICFERAppIdentityDbContext(DbContextOptions<ICFERAppIdentityDbContext> options)
        : base(options)
    {
    }

    protected override void OnModelCreating(ModelBuilder builder)
    {
        base.OnModelCreating(builder);
        // Customize the ASP.NET Identity model and override the defaults if needed.
        // For example, you can rename the ASP.NET Identity table names and more.
        // Add your customizations after calling base.OnModelCreating(builder);
    }
}

但我这里有一个现有的：

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

        public DbSet<Student> Students { get; set; }

        protected override void OnModelCreating(ModelBuilder builder)
        {
            base.OnModelCreating(builder);

            builder.Entity<ApplicationUser>()
                .HasMany(s => s.Students)
                .WithOne(u => u.User);


            builder.Entity<Student>()
                .HasOne(e => e.Education)
                .WithOne(s => s.Student);


            builder.Entity<Student>()
                .HasOne(g => g.Guardian)
                .WithOne(s => s.Student);

            builder.Entity<Student>()
                .HasOne(p => p.Parents)
                .WithOne(s => s.Student);

            builder.Entity<Student>()
                .HasOne(s => s.Siblings)
                .WithOne(s => s.Student);

            builder.Entity<Siblings>()
                .Property(p => p.Id)
                .ValueGeneratedOnAdd();

            builder.Entity<Siblings>()
                .HasKey(x => new { x.Id, x.StudentId});

            builder.Entity<Education>()
                .Property(p => p.Id)
                .ValueGeneratedOnAdd();

            builder.Entity<Education>()
                .HasKey(x => new { x.Id, x.StudentId});


            builder.Entity<Guardian>()
                .Property(p => p.Id)
                .ValueGeneratedOnAdd();

            builder.Entity<Guardian>()
                .HasKey(x => new { x.Id, x.StudentId});
            builder.Entity<Parents>()
                .Property(p => p.Id)
                .ValueGeneratedOnAdd();

            builder.Entity<Parents>()
                .HasKey(x => new { x.Id, x.StudentId});


        }
    }

然后，在我的 Startup.cs 文件中，我遵循了 Microsoft doc 所说的内容：

public class Startup
    {
        public Startup(IConfiguration configuration)
        {
            Configuration = configuration;
        }

        public IConfiguration Configuration { get; }

        // This method gets called by the runtime. Use this method to add services to the container.
        public void ConfigureServices(IServiceCollection services)
        {
            services.Configure<CookiePolicyOptions>(options =>
            {
                // This lambda determines whether user consent for non-essential cookies is needed for a given request.
                options.CheckConsentNeeded = context => true;
                options.MinimumSameSitePolicy = SameSiteMode.None;
            });

            services.AddIdentity<ApplicationUser, IdentityRole>()
                .AddDefaultUI(UIFramework.Bootstrap4)
                .AddEntityFrameworkStores<ApplicationDbContext>()
                .AddDefaultTokenProviders();

            services.AddDbContext<ApplicationDbContext>(options =>
                options.UseMySql(
                    Configuration.GetConnectionString("DefaultConnection")));


            services.AddTransient<IStudentRepository, StudentRepository>();
            services.AddMvc().AddNToastNotifyToastr();


            services.AddJsReport(new LocalReporting()
                .UseBinary(RuntimeInformation.IsOSPlatform(OSPlatform.Windows)
                    ? JsReportBinary.GetBinary()
                    : jsreport.Binary.OSX.JsReportBinary.GetBinary())
                .AsUtility()
                .Create());

            services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_2);


            services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_1)
                .AddRazorPagesOptions(options =>
                {
                    options.AllowAreas = true;
                    options.Conventions.AuthorizeAreaFolder("Identity", "/Account/Manage");
                    options.Conventions.AuthorizeAreaPage("Identity", "/Account/Logout");
                });

            services.ConfigureApplicationCookie(options =>
            {
                options.LoginPath = $"/Identity/Account/Login";
                options.LogoutPath = $"/Identity/Account/Logout";
                options.AccessDeniedPath = $"/Identity/Account/AccessDenied";
            });
        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IHostingEnvironment env)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
                app.UseDatabaseErrorPage();
            }
            else
            {
                app.UseExceptionHandler("/Home/Error");
                // The default HSTS value is 30 days. You may want to change this for production scenarios, see https://aka.ms/aspnetcore-hsts.
                app.UseHsts();
            }

            app.UseHttpsRedirection();
            app.UseStaticFiles();
            app.UseCookiePolicy();
            app.UseNToastNotify();

            app.UseAuthentication();

            app.UseMvc(routes =>
            {
                routes.MapRoute(
                    name: "default",
                    template: "{controller=Student}/{action=Index}/{id?}");
            });
        }
    }

有了以上所有信息，我的实现到底出了什么问题？

Answer 1

检查IdentityHostingStartup.cs，如果它退出，请在下面注释掉：

services.AddDefaultIdentity<IdentityUser>()
    .AddEntityFrameworkStores<ICFERAppIdentityDbContext>();

简而言之，只需要一种身份配置。 Here 是相关讨论。