Asp.net 无法解析类型为'；MyApp.ApplicationDbContext'；试图激活时

在集成到现有ASP.NETCore2.0应用程序中后，我遇到了一个问题，即基于ASP.NETCore2.0的新创建的身份验证项目项

经过一些调整，然后成功构建，在浏览器中我得到了下一个错误：

处理请求时发生未处理的异常。

InvalidOperationException:尝试激活时无法解析类型为“SpaServices.ApplicationDbContext”的服务

身份验证必须使用尚未搭建的单独数据库

我的Startup.cs如下所示：

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.AddDbContext<SchoolContext>(options =>
        options.UseSqlServer(Configuration.GetConnectionString("DefaultConnection")));

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

    services.AddMvc()
        .AddRazorPagesOptions(options =>
         {
             options.Conventions.AuthorizeFolder("/Account/Manage");
             options.Conventions.AuthorizePage("/Account/Logout");
         });

    // Register no-op EmailSender used by account confirmation and password reset during development
    // For more information on how to enable account confirmation and password reset please visit https://go.microsoft.com/fwlink/?LinkID=532713
    services.AddSingleton<IEmailSender, EmailSender>();

}

// 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();

    #region webpack-middleware-registration
    if (env.IsDevelopment())
    {
        app.UseDeveloperExceptionPage();
        app.UseWebpackDevMiddleware();
    }
    else
    {
        app.UseExceptionHandler("/Home/Error");
    }

    // Call UseWebpackDevMiddleware before UseStaticFiles
    app.UseStaticFiles();
    #endregion

    #region mvc-routing-table
    app.UseMvc(routes =>
    {
        routes.MapRoute(
            name: "default",
            template: "{controller=Home}/{action=Index}/{id?}");

        routes.MapSpaFallbackRoute(
            name: "spa-fallback",
            defaults: new { controller = "Home", action = "Index" });
    });
    #endregion
}

---

如果不成功，有什么想法吗？

您需要在ConfigureServices（）方法中包括以下内容：

services.AddDbContext（选项=>
options.UseSqlServer（Configuration.GetConnectionString（“[您的连接字符串标识符]”））；

---

目前，您只添加了“SchoolContext”DbContext，您需要在ConfigureServices（）方法中包括以下内容：

services.AddDbContext（选项=>
options.UseSqlServer（Configuration.GetConnectionString（“[您的连接字符串标识符]”））；

---

目前，您只添加了一个“SchoolContext”DbContext

有时会发生愚蠢的错误，这就是其中之一。是的，您是对的，我添加了它，然后按照上面的方法重新更新构造函数，以显式地期望容器知道如何解析的类型，然后它就工作了。有时会发生愚蠢的错误，这是一个。是的，你是对的，我添加了它，然后像上面一样重新更新了构造函数，以显式地期望容器知道如何解析类型，然后它工作了。

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

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

    }
}

public ApplicationDbContext(DbContextOptions options)
    : base(options)
    {
    }

 services.AddDbContext<ApplicationDbContext>(options =>
  options.UseSqlServer(Configuration.GetConnectionString("[Your Connection String Identifier]")));