how to get value from appsettings.json

Question

public class Bar
{
    public static readonly string Foo = ConfigurationManager.AppSettings[\"Foo\"];
}

In the .NET Framework 4.x, I can use the

Answer 1

Addition to answer from @MindingData. I like to map my settings recursively using Configuration.Bind(settings); so that I don't have to add every new section in ConfigureServices.

Example:

appsettings.json:

{
    "MyConfiguration": {
        "MyProperty": true 
    }
}

Settings class, properties must match appsettings.json names:

public class Settings
{

    public MyConfigurationSettings MyConfiguration { get; set; }

    public class MyConfigurationSettings
    {
        public bool MyProperty { get; set; }
    }

}

Startup.cs

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 settings = new Settings();
        Configuration.Bind(settings);
        services.AddSingleton(settings);
        ...

Can be used in controllers like this:

[Route("api/[controller]")]
[ApiController]
public class ValuesController : ControllerBase
{
    private readonly Settings _settings;

    public ValuesController(Settings settings)
    {
        _settings = settings;
    }

    [HttpGet("GetValue")]
    public ActionResult Get()
    {
        return Ok(_settings.MyConfiguration.MyProperty);
    }
}