尝试在.NET CORE Web应用程序中创建控制器时出错 [英] Error when trying to create a Controller in .NET CORE Web Application

问题描述

我在Visual Studio 2017中创建了一个.NET CORE Web应用程序.它是作为一个空模板创建的.

I have a .NET CORE Web application created in Visual Studio 2017. It was created as a empty template.

startup.cs具有以下代码

The startup.cs has the below code

    public void ConfigureServices(IServiceCollection services)
    {
        services.AddMvc();
        services.AddSingleton<IInventoryServices, InventoryServices>();
    }

    public void Configure(IApplicationBuilder app, IHostingEnvironment env)
    {
        if (env.IsDevelopment())
        {
            app.UseDeveloperExceptionPage();
        }
        app.UseMvcWithDefaultRoute();
    }

program.cs如下:

The program.cs is like below:

public class Program
{
    public static void Main(string[] args)
    {
        CreateWebHostBuilder(args).Build().Run();
    }

    public static IWebHostBuilder CreateWebHostBuilder(string[] args) => 
WebHost.CreateDefaultBuilder(args).UseStartup<Startup>();
}

我试图创建一个控制器.我选择添加的控制器的类型为使用Entity Framework的具有视图的MVC控制器".尝试创建时，我在窗口中指定了模型类，并在生成视图"，参考脚本库"和使用布局页面"中打了勾，默认情况下已打勾.用于指定布局"页面的文本框保留为空白.

I tried to create a Controller. The type of the controller I selected to add was "MVC Controller with views, using Entity Framework". When trying to create, in the window i have specified the model class, and ticked for "Generate views", "Reference script libraries" and "Use layout page" which by the way are ticked by default. The text-box to specify the Layout page is left blank.

尝试创建控制器时，出现以下错误:

When trying to create the controller I get the below error:

运行所选代码生成器时发生错误:脚手架无法编辑Startup类以使用注册新的Context依赖注入.确保有一个Startup类和一个其中的配置属性

There was an error running the selected code generator: Scaffolding failed to edit Startup class to register the new Context using Dependency injection. Make sure there is a Startup class and a Configuration property in it

无法弄清楚为什么会发生此错误.是因为DI还是实体上下文问题?

Couldn't figure out why this error is happening. Is it because of DI or Entity Context issue ?

推荐答案

您还必须确保DbContext也已在Startup类 ConfigureServices()方法中注册.

You would have to make sure that the DbContext is registered in the Startup class ConfigureServices() method as well.

首次注入 IConfiguration 接口:

public IConfiguration Configuration { get; }

    public Startup(IConfiguration configuration)
        {
            Configuration = configuration;
        }

然后将以下代码添加到ConfigureServices方法:

then Add Below Code To ConfigureServices Method:

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

，然后在 appsettings.json 中添加ConnectionString地址:

and then Add ConnectionString Address in appsettings.json :

{
  "ConnectionStrings": {
    "DefaultConnection": "Server=(localdb)\\mssqllocaldb;Database=YourDatabaseName;Trusted_Connection=True;MultipleActiveResultSets=true"
  } 
}

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