ASP.NET MVC 6 Connection Sting config.json

Question

Проблема, с которой я столкнулась, - это когда я запускаю программу, я получаю исключение «Исключение System.NullReferenceException». Не знаю, в чем проблема. Эта проблема также не позволяет мне начать миграцию данных с помощью dnx.

#config.json 

{ 
    "Data": { 
    "DefaultConnection": { 
    "Connectionstring": "Data Server=.\\ERKANDEMIR5E91;Initial Catalog=RegistrationDB;Integrated Security=True;" 
     } 
    } 
} 

scoolDbContext.cs

using System; 
using System.Collections.Generic; 
using System.Linq; 
using System.Threading.Tasks; 
using Microsoft.Data.Entity; 
using Microsoft.Data.Entity.Metadata; 
using School.Models; 

namespace School.Context 
{ 
    public class SchoolDbContext : DbContext 
    { 
     public DbSet<Course> Courses {get; set;} 
    } 
} 

Statup.cs

namespace School 
{ 
public class Startup 
{ 
    public static Microsoft.Extensions.Configuration.IConfiguration Configuration { get; set; } 

    public Startup (IHostingEnvironment env) 
    { 
     //setup configuration sources 
     Configuration = new ConfigurationBuilder() 
     .AddJsonFile("config.json") 
     .AddEnvironmentVariables() 
     .Build(); 

    } 
    // This method gets called by the runtime. Use this method to add services to the container. 
    // For more information on how to configure your application, visit http://go.microsoft.com/fwlink/?LinkID=398940 
    public void ConfigureServices(IServiceCollection services) 
    { 
     //add services to container 
     services.AddEntityFramework().AddSqlServer().AddDbContext<SchoolDbContext>(options => options.UseSqlServer(Configuration["Data:DefaultConnection:ConnectionString"])); 
     services.AddMvc(); 

     //resolve dependency injections 
     services.AddScoped<IRegistrationRepo, RegistrationRepo>(); 
     services.AddScoped<SchoolDbContext, SchoolDbContext>();   
    } 

    // This method gets called by the runtime. Use this method to configure the HTTP request pipeline. 
    public void Configure(IApplicationBuilder app) 
    { 
     app.UseIISPlatformHandler(); 
     app.UseMvc(); 
     app.UseWelcomePage(); 

    } 

    // Entry point for the application. 
    public static void Main(string[] args) => WebApplication.Run<Startup>(args); 
    } 
} 

Answer 1

Вы должны исправить код

public Startup (IHostingEnvironment env) 
{ 
    //setup configuration sources 
    Configuration = new Configuration() 
     .AddJsonFile("config.json") 
     .AddEnvironmentVariables(); 
} 

в

public Startup (IHostingEnvironment env) 
{ 
    //setup configuration sources 
    Configuration = new ConfigurationBuilder() 
     .AddJsonFile("config.json") 
     .AddEnvironmentVariables() 
     .Build(); 
} 

или

public Startup (IHostingEnvironment env) 
{ 
    //setup configuration sources 
    Configuration = new ConfigurationBuilder() 
     .AddJsonFile("config.json") 
     .AddJsonFile($"config.{env.EnvironmentName}.json", true) 
     .AddEnvironmentVariables() 
     .Build(); 
}