从.net core 1.1 web api中的appsettings.json读取连接

Question

我在.net核心1.1中创建了一个web api项目，但问题是当它尝试从appsettings.json读取connectionstring时发生异常。

  

System.IO.FileNotFoundException：'配置文件   'appsettings.json'找不到，也不是可选的。身体上的   路径是   'C：\测试\ netCoreWebApi \ netCoreWebApi \ BIN \调试\ netcoreapp1.1 \ appsettings.json'。'

Startup.cs

public class Startup
    {
        public Startup(IHostingEnvironment env)
        {
            var builder = new ConfigurationBuilder()
                .SetBasePath(env.ContentRootPath)
                .AddJsonFile("appsettings.json", optional: false, 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)
        {
            services.AddDbContext<NorthWindDBContext>();
            // Add framework services.
            services.AddMvc();

            services.AddScoped<ICategory_Product, Category_ProductRepository>();
        }

        // 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();

            app.UseMvc();
        }
    }

也是DBContext类中的eclare connectionstring（可能我在这里做错了）

protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
        {
            var builder = new ConfigurationBuilder()
                       .AddJsonFile("appsettings.json", optional: false, reloadOnChange: true);

            var configuration = builder.Build();

            string connectionString = configuration.GetConnectionString("northwindConnection");
            optionsBuilder.UseMySql(connectionString);


        }

所以这是正确的方式。

请帮忙。