ASP.NET Core:JSON配置GetSection返回null

Question

我有一个appsettings.json看起来像这样的文件:

{
    "MyConfig": {
        "ConfigA": "value",
        "ConfigB": "value"
    }
}

在我的Startup.cs建设中IConfiguration:

public ConfigurationRoot Configuration { get; set; }

public Startup(ILoggerFactory loggerFactory, IHostingEnvironment environment)
{
      var builder = new ConfigurationBuilder()
                     .SetBasePath(environment.ContentRootPath)
                     .AddJsonFile("appsettings.json", optional: false, reloadOnChange: true)                             
                     .AddEnvironmentVariables();

      Configuration = builder.Build();
}

public void ConfigureServices(IServiceCollection services)
{
      //GetSection returns null...
      services.Configure<MyConfig>(Configuration.GetSection("MyConfig"));
}

但Configuration.GetSection("MyConfig")总是返回null,尽管我的JSON文件中存在该值.Configuration.GetSection("MyConfig:ConfigA")工作得很好.

我究竟做错了什么？

Answer 1

对于遇到这种情况并试图在测试项目中做同样事情的人来说，这对我有用：

other = config.GetSection("OtherSettings").Get<OtherSettings>();

Answer 2

请参考下面的代码

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

    public IConfiguration Configuration { get; }

    // This method gets called by the runtime. Use this method to add services to the container.
    public void ConfigureServices(IServiceCollection services)
    {
        var config = Configuration.GetSection("MyConfig");
        // To get the value configA
        var value = config["ConfigA"];

        // or direct get the value
        var configA = Configuration.GetSection("MyConfig:ConfigA");

        var myConfig = new MyConfig();
        // This is to bind to your object
        Configuration.GetSection("MyConfig").Bind(myConfig);
        var value2 = myConfig.ConfigA;
    }
}