无效操作异常错误

Question

您好，我收到此错误：

无效操作异常： 无法解析类型的服务 "RegistrationMVC.Model.OurDbContext"，同时尝试激活 "注册MVC.Controllers.HomeController"。

我不知道是什么原因造成的，可能是有依赖关系的东西吗？

启动.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
using WebApplicationCore.NetCore.DataAccess;
using WebApplicationCore.NetCore.BusinessLogic;
namespace WebApplicationCore.NetCore
    public class Startup
    {
        public Startup(IHostingEnvironment env)
        {
            var builder = new ConfigurationBuilder()
                .SetBasePath(env.ContentRootPath)
                .AddJsonFile("appsettings.json", optional: true, reloadOnChange: true)
                .AddJsonFile($"appsettings.{env.EnvironmentName}.json", optional: true)
                .AddEnvironmentVariables();
            Configuration = builder.Build();
        }
    public IConfigurationRoot Configuration { get; }
    // This method gets called by the runtime. Use this method to add services to the container.
    public void ConfigureServices(IServiceCollection services)
    {
        // Add framework services.
        services.AddMvc();
        services.AddSingleton<IConfigurationRoot>(sp => { return this.Configuration; });
        services.AddScoped<IContactDataAccess, ContactDataAccess>();
        services.AddScoped<IContactBusinessLogic, ContactBusinessLogic>();
    }
    // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
    public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory)
    {
        loggerFactory.AddConsole(Configuration.GetSection("Logging"));
        loggerFactory.AddDebug();
        if (env.IsDevelopment())
        {
            app.UseDeveloperExceptionPage();
            app.UseBrowserLink();
        }
        else
        {
            app.UseExceptionHandler("/Home/Error");
        }
        app.UseStaticFiles();
        app.UseMvc(routes =>
        {
            routes.MapRoute(
                name: "default",
                template: "{controller=Home}/{action=Index}/{id?}");
        });
    }
}

首页控制器

OurDbContext

Answer 1

一些容器会自动实例化像 OurDbContext 这样的类(只要它可以成功构造(，因为它是一个可以构造的类型，而另一些容器如果未在依赖项容器中定义 OurDbContext，则会引发异常。 所以它可以像没有注册我们的数据库上下文一样简单，并且容器以这种方式运行......