'Microsoft.AspNetCore.Identity.UserManager`1[Alpha.Models.Identity.User]‘核心3:无法从根提供程序解析作用域服务ASP.NET
当我运行这个项目时，我遇到了以下问题：(我使用了asp.net core 3)。
'Microsoft.AspNetCore.Identity.UserManager`1Alpha.Models.Identity.User‘无法从根提供程序解析作用域服务
。
我该如何解决这个问题？
ApplicationDbContext类：
public class ApplicationDbContext : IdentityDbContext<User, Role, int,
UserClaim, UserRole, UserLogin, RoleClaim, UserToken>
{
public ApplicationDbContext(DbContextOptions<ApplicationDbContext> options) : base(options)
{
}
public static async Task CreateAdminAccount(IServiceProvider
serviceProvider, IConfiguration configuration)
{
UserManager<User> userManager =
serviceProvider.GetRequiredService<UserManager<User>>();
RoleManager<Role> roleManager =
serviceProvider.GetRequiredService<RoleManager<Role>>();
string userName = configuration["Data:AdminUser:Name"];
string email = configuration["Data:AdminUser:Email"];
string password = configuration["Data:AdminUser:Password"];
string role = configuration["Data:AdminUser:Role"];
if (await userManager.FindByNameAsync(userName) == null)
{
if (await roleManager.FindByNameAsync(role) == null)
{
await roleManager.CreateAsync(new Role(role));
}
User user = new User
{
Email = email,
UserName = userName
};
var result = userManager.CreateAsync(user, password);
if (result.IsCompletedSuccessfully)
{
await userManager.AddToRoleAsync(user, role);
}
}
}
}错误的详细信息：
启动应用程序时发生错误。AggregateException:发生了一个或多个错误。(无法从根提供程序解析作用域服务'Microsoft.AspNetCore.Identity.UserManager
1[Alpha.Models.Identity.User]' from root provider.) System.Threading.Tasks.Task.ThrowIfExceptional(bool includeTaskCanceledExceptions) InvalidOperationException: Cannot resolve scoped service 'Microsoft.AspNetCore.Identity.UserManager1Alpha.Models.Identity.User‘。Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteValidator.ValidateResolution(Type serviceType，IServiceScope范围，IServiceScope rootScope)
AggregateException:发生了一个或多个错误。(无法从根提供程序解析作用域服务'Microsoft.AspNetCore.Identity.UserManager1[Alpha.Models.Identity.User]' from root provider.) System.Threading.Tasks.Task.ThrowIfExceptional(bool includeTaskCanceledExceptions) System.Threading.Tasks.Task.Wait(int millisecondsTimeout, CancellationToken cancellationToken) System.Threading.Tasks.Task.Wait() Alpha.Web.App.Startup.Configure(IApplicationBuilder app, IWebHostEnvironment env) in Startup.cs + ApplicationDbContext.CreateAdminAccount(app.ApplicationServices, Configuration).Wait(); System.RuntimeMethodHandle.InvokeMethod(object target, object[] arguments, Signature sig, bool constructor, bool wrapExceptions) System.Reflection.RuntimeMethodInfo.Invoke(object obj, BindingFlags invokeAttr, Binder binder, object[] parameters, CultureInfo culture) Microsoft.AspNetCore.Hosting.ConfigureBuilder.Invoke(object instance, IApplicationBuilder builder) Microsoft.AspNetCore.Hosting.ConfigureBuilder+<>c\_\_DisplayClass4\_0.b\_\_0(IApplicationBuilder builder) Microsoft.AspNetCore.Hosting.GenericWebHostBuilder+<>c\_\_DisplayClass13\_0.b\_\_2(IApplicationBuilder app) Microsoft.AspNetCore.Mvc.Filters.MiddlewareFilterBuilderStartupFilter+<>c\_\_DisplayClass0\_0.g\_\_MiddlewareFilterBuilder|0(IApplicationBuilder builder) Microsoft.AspNetCore.Server.IIS.Core.IISServerSetupFilter+<>c\_\_DisplayClass2\_0.b\_\_0(IApplicationBuilder app) Microsoft.AspNetCore.HostFilteringStartupFilter+<>c\_\_DisplayClass0\_0.b\_\_0(IApplicationBuilder app) Microsoft.AspNetCore.Hosting.GenericWebHostService.StartAsync(CancellationToken cancellationToken) Microsoft.Extensions.Hosting.Internal.Host.StartAsync(CancellationToken cancellationToken) Microsoft.Extensions.Hosting.HostingAbstractionsHostExtensions.RunAsync(IHost host, CancellationToken token) Microsoft.Extensions.Hosting.HostingAbstractionsHostExtensions.RunAsync(IHost host, CancellationToken token) Microsoft.Extensions.Hosting.HostingAbstractionsHostExtensions.Run(IHost host) Alpha.Web.App.Program.Main(string[] args) in Program.cs + CreateHostBuilder(args).Build().Run(); Show raw exception details InvalidOperationException: Cannot resolve scoped service 'Microsoft.AspNetCore.Identity.UserManager1Alpha.Models.Identity.User‘。Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteValidator.ValidateResolution(Type serviceType，IServiceScope scope，IServiceScope rootScope) Microsoft.Extensions.DependencyInjection.ServiceProvider.Microsoft.Extensions.DependencyInjection.ServiceLookup.IServiceProviderEngineCallback.OnResolve(Type serviceType，IServiceScope scope) Microsoft.Extensions.DependencyInjection.ServiceLookup.ServiceProviderEngine.GetService(Type serviceType，ServiceProviderEngineScope serviceProviderEngineScope) Microsoft.Extensions.DependencyInjection.ServiceLookup.ServiceProviderEngineScope.GetService(Type serviceType) Microsoft.Extensions.DependencyInjection.ServiceProviderServiceExtensions.GetRequiredService(IServiceProvider提供者，Microsoft.Extensions.DependencyInjection.ServiceProviderServiceExtensions.GetRequiredService(IServiceProvider提供者( Alpha.DataAccess.ApplicationDbContext.CreateAdminAccount(IServiceProvider serviceProvider，IConfiguration configuration)在ApplicationDbContext.cs + UserManager userManager =serviceProvider.GetRequiredService>()中输入；
显示原始异常详细信息System.InvalidOperationException:无法从根提供程序解析作用域服务System.InvalidOperationException。在Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteValidator.ValidateResolution(Type serviceType，IServiceScope scope，IServiceScope rootScope at Microsoft.Extensions.DependencyInjection.ServiceProvider.Microsoft.Extensions.DependencyInjection.ServiceLookup.IServiceProviderEngineCallback.OnResolve(Type serviceType，IServiceScope scope)在Microsoft.Extensions.DependencyInjection.ServiceLookup.ServiceProviderEngine.GetService(Type serviceType，ServiceProviderEngineScope serviceProviderEngineScope)
(在Microsoft.Extensions.DependencyInjection.ServiceLookup.ServiceProviderEngineScope.GetService(Type serviceType)在Microsoft.Extensions.DependencyInjection.ServiceProviderServiceExtensions.GetRequiredService(IServiceProvider provider上，在Microsoft.Extensions.DependencyInjection.ServiceProviderServiceExtensions.GetRequiredServiceT at Alpha.DataAccess.ApplicationDbContext.CreateAdminAccount(IServiceProvider serviceProvider (输入serviceType)，( E:\Archives\Projects\Alpha\Alpha.DataAccess\ApplicationDbContext.cs:line 92 .NET Core 3.0.0 X64 v4.0.0.0 Microsoft.AspNetCore.Hosting version 3.0.0-rc2.19465.2 \MicrosoftWindows10.0.17763 X64)中的.NET配置
需要帮助吗？
回答 1
Stack Overflow用户
发布于 2019-10-26 22:15:37
从包含的屏幕截图中可以看出，在Startup.Configure中有下面一行
ApplicationDbContext.CreateAdminAccount(app.ApplicationServices, Configuration)
.Wait();存储在IServiceProvider中的IApplicationBuilder.ApplicationServices实例是应用程序的根服务提供程序。错误消息声明它无法解析根服务提供程序的作用域服务。
这个问题经常出现，但是您的场景中最简单的解决方案是将IServiceProvider注入您的Configure方法并将其传递给CreateAdminAccount。
public void Configure(IApplicationBuilder app, IServiceProvider serviceProvider)
{
ApplicationDbContext.CreateAdminAccount(serviceProvider, Configuration)
.Wait();
}传递给IServiceProvider的Configure实例是作用域，这意味着您可以使用它创建作用域服务。
这就是您需要做的全部工作，但是在Program中执行这种类型的种子比较典型。这使得种子问题与配置管道分离，并且还允许使用async/await。下面是一个例子：
public class Program
{
public static async Task Main(string[] args)
{
var host = CreateHostBuilder(args).Build();
using (var scope = host.Services.CreateScope())
{
var serviceProvider = scope.ServiceProvider;
var config = serviceProvider.GetRequiredService<IConfiguration>();
await ApplicationDbContext.CreateAdminAccount(serviceProvider, config);
}
await host.RunAsync();
}
public static IHostBuilder CreateHostBuilder(string[] args) =>
// ...
}您也可以在UserManager<User>中解析Main和RoleManager<Role>，并将它们传递给CreateAdminAccount，而不是让它使用服务定位器方法。
https://stackoverflow.com/questions/58574899
复制相似问题
腾讯云开发者
