当通过ef核心删除数据库时，发生了扩展提升错误

Question

我正在.Net core应用程序中添加数据标识实体框架核心。我已经在我的应用程序中安装了Microsoft.AspNetCore.Identity。EntityFrameworkCore，在尝试删除数据库时，我收到了一个错误

访问Microsoft.Extensions.Hosting服务时出错。在没有应用程序服务提供商的情况下继续。错误：无法构造某些服务(验证服务描述符"ServiceType:Microsoft.AspNetCore.Identity。ISecurityStampValidator Lifetime:Scoped ImplementationType:Microsoft.阿斯pNetCorE.Identity。SecurityStampValidator1[Domain.AppUser]': Unable to resolve service for type 'Microsoft.AspNetCore.Authentication.ISystemClock' while attempting to activate 'Microsoft.AspNetCore.Identity.SecurityStampValidator1[Domain.AppUser]"时出错。((验证服务描述符"ServiceType:Microsoft.AspNetCore.Identity.ITwoFactorSecurityStampValidator Lifetime:Scoped ImplementationType:Microsoft.阿斯pNetCorE.Identity.TwoFactorSecurityStamp Validator1[Domain.AppUser]': Unable to resolve service for type 'Microsoft.AspNetCore.Authentication.ISystemClock' while attempting to activate 'Microsoft.AspNetCore.Identity.TwoFactorSecurityStampValidator1[Domain.AppUser]"时出错。(无法创建"DataContext"类型的对象。有关设计时支持的不同模式，请参阅https://go.microsoft.com/fwlink/?linkid=851728

我的DataContext类是

using System;
using Domain;
using Microsoft.AspNetCore.Identity.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore;
namespace Persistence
{
public class DataContext : IdentityDbContext<AppUser>
{
public DataContext(DbContextOptions options) : base(options)
{
}
public DbSet<Value> Values { get; set; }
public DbSet<Activity> Acitivities {get;set;}
protected override void OnModelCreating(ModelBuilder builder)
{
base.OnModelCreating(builder);
}
}
}

我的Startup.cs课程是

using API.Middleware;
using Application.Activities;
using Domain;
using FluentValidation.AspNetCore;
using MediatR;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Identity;
using Microsoft.AspNetCore.Mvc;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using Persistence;
namespace API
{
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.AddDbContext<DataContext>(opt => {
opt.UseSqlite(Configuration.GetConnectionString("DefaultConnection"));
});
services.AddControllers();
services.AddMvc(option => option.EnableEndpointRouting = false)
.AddFluentValidation(cfg => cfg.RegisterValidatorsFromAssemblyContaining<Create>());

var builder = services.AddIdentityCore<AppUser>();
var identityBuilder = new IdentityBuilder(builder.UserType, builder.Services);
identityBuilder.AddEntityFrameworkStores<DataContext>();
identityBuilder.AddSignInManager<SignInManager<AppUser>>();
}
// This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{
app.UseMiddleware<ErrorHandlingMiddleware>();

if (env.IsDevelopment())
{
// app.UseDeveloperExceptionPage();
}
// app.UseHttpsRedirection();
app.UseCors("CorsPolicy");
app.UseRouting();
app.UseAuthorization();
app.UseEndpoints(endpoints =>
{
endpoints.MapControllers();
}); 
}
}
}

我的AppUser.cs类是

using Microsoft.AspNetCore.Identity;
using System;
using System.Collections.Generic;
using System.Text;
namespace Domain
{
public class AppUser : IdentityUser
{
public string DisplayName { get; set; }
}
}

我在这里做错了什么？

Answer 1

我刚刚在var builder = services.AddIdentityCore<AppUser>();之前添加了services.TryAddSingleton<ISystemClock, SystemClock>();，它可以很好地