Estou com o problema abaixo e não sei por onde corrigir. Teria alguém para me auxiliar? Estou usando o banco SqlServer, a API só dá esse problema depois de inserir as linhas de código referente a Roles.
System.AggregateException: One or more errors occurred. (A second operation was started on this context before a previous operation completed. This is usually caused by different threads concurrently using the same instance of DbContext. For more information on how to avoid threading issues with DbContext, see https://go.microsoft.com/fwlink/?linkid=2097913.)
---> System.InvalidOperationException: A second operation was started on this context before a previous operation completed. This is usually caused by different threads concurrently using the same instance of DbContext. For more information on how to avoid threading issues with DbContext, see https://go.microsoft.com/fwlink/?linkid=2097913.
at Microsoft.EntityFrameworkCore.Internal.ConcurrencyDetector.EnterCriticalSection()
at Microsoft.EntityFrameworkCore.Query.Internal.SingleQueryingEnumerable1.AsyncEnumerator.MoveNextAsync()
at Microsoft.EntityFrameworkCore.Query.ShapedQueryCompilingExpressionVisitor.SingleOrDefaultAsync[TSource](IAsyncEnumerable1 asyncEnumerable, CancellationToken cancellationToken)
at Microsoft.EntityFrameworkCore.Query.ShapedQueryCompilingExpressionVisitor.SingleOrDefaultAsync[TSource](IAsyncEnumerable1 asyncEnumerable, CancellationToken cancellationToken)
at Microsoft.AspNetCore.Identity.RoleValidator1.ValidateRoleName(RoleManager1 manager, TRole role, ICollection1 errors)
at Microsoft.AspNetCore.Identity.RoleValidator1.ValidateAsync(RoleManager1 manager, TRole role)
at Microsoft.AspNetCore.Identity.RoleManager1.ValidateRoleAsync(TRole role)
at Microsoft.AspNetCore.Identity.RoleManager1.CreateAsync(TRole role)
--- End of inner exception stack trace ---
at System.Threading.Tasks.Task1.GetResultCore(Boolean waitCompletionNotification)
at System.Threading.Tasks.Task1.get_Result()
at UsuariosApi.Services.CadastroService.CadastraUsuario(CreateUsuarioDto createDto) in C:\Users\PROGRAMACAOFLP\Desktop\alura-csharp-4-projeto-Aula-3\UsuariosApi\Services\CadastroService.cs:line 37
at UsuariosApi.Controllers.CadastroController.CadastraUsuario(CreateUsuarioDto createDto) in C:\Users\PROGRAMACAOFLP\Desktop\alura-csharp-4-projeto-Aula-3\UsuariosApi\Controllers\CadastroController.cs:line 28
at lambda_method2(Closure , Object , Object[] )
at Microsoft.AspNetCore.Mvc.Infrastructure.ActionMethodExecutor.SyncActionResultExecutor.Execute(IActionResultTypeMapper mapper, ObjectMethodExecutor executor, Object controller, Object[] arguments)
at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.InvokeActionMethodAsync()
at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted)
at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.InvokeNextActionFilterAsync()
--- End of stack trace from previous location ---
at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Rethrow(ActionExecutedContextSealed context)
at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted)
at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.InvokeInnerFilterAsync()
--- End of stack trace from previous location ---
at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.g__Awaited|19_0(ResourceInvoker invoker, Task lastTask, State next, Scope scope, Object state, Boolean isCompleted)
at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.g__Awaited|17_0(ResourceInvoker invoker, Task task, IDisposable scope)
at Microsoft.AspNetCore.Routing.EndpointMiddleware.g__AwaitRequestTask|6_0(Endpoint endpoint, Task requestTask, ILogger logger)
at Microsoft.AspNetCore.Authorization.AuthorizationMiddleware.Invoke(HttpContext context)
at Swashbuckle.AspNetCore.SwaggerUI.SwaggerUIMiddleware.Invoke(HttpContext httpContext)
at Swashbuckle.AspNetCore.Swagger.SwaggerMiddleware.Invoke(HttpContext httpContext, ISwaggerProvider swaggerProvider)
at Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware.Invoke(HttpContext context)
