[ASP.NET Core] Get values from IConfiguration

{  "Logging": {    "LogLevel": {      "Default": "Information",      "Microsoft.AspNetCore": "Warning"    }  },  "AllowedHosts": "*"}

{  "Logging": {    "LogLevel": {      "Default": "Debug",      "Microsoft.AspNetCore": "Warning"    }  },  "SampleText": "Hello",  "SampleNumber": 3,  "SampleBoolean": true,  "SampleArray": ["Hello", "World"],  "SampleBook": { "id": 5, "name": "Sample"},  "SampleBooks": [{ "Id": 6, "Name": "Sample1"},    { "Id": 7, "Name": "Sample2"}],  "NullSample": null}

using NLog.Web;var logger = NLogBuilder.ConfigureNLog("Nlog.config").GetCurrentClassLogger();try {    var builder = WebApplication.CreateBuilder(args);    builder.Host.ConfigureLogging(logging =>    {        logging.ClearProviders();        logging.AddConsole();    })    .UseNLog();    builder.Services.AddControllers();    var app = builder.Build();    app.UseRouting();    app.UseEndpoints(endpoints =>    {        endpoints.MapControllers();    });    app.Run();}catch(Exception ex){    logger.Error(ex, "Stopped program because of exception");}finally{    NLog.LogManager.Shutdown();}

namespace ConfigSample.Books.Models;public record Book{    public int Id { get; init; }    public string Name { get; init; } = "";}

using ConfigSample.Books.Models;using Microsoft.AspNetCore.Mvc;namespace ConfigSample.Controllers;public class HomeController: Controller{    private readonly ILogger<HomeController> logger;    private readonly IConfiguration config;    public HomeController(ILogger<HomeController> logger,        IConfiguration config)    {        this.logger = logger;        this.config = config;    }    [Route("")]    public string Index()    {        // get values and log them here.        return "Hello World";    }}

...    [Route("")]    public string Index()    {        // get values and log them here.        this.logger.LogDebug(this.config["SampleText"]);        this.logger.LogDebug(this.config["SampleNumber"]);        this.logger.LogDebug(this.config["SampleBoolean"]);        this.logger.LogDebug(this.config["NullSample"]);        return "Hello World";    }...

dbug: ConfigSample.Controllers.HomeController[0]      Hello2022-02-21 01:28:32.2159||DEBUG|ConfigSample.Controllers.HomeController|Hellodbug: ConfigSample.Controllers.HomeController[0]      32022-02-21 01:28:32.2342||DEBUG|ConfigSample.Controllers.HomeController|3dbug: ConfigSample.Controllers.HomeController[0]      True2022-02-21 01:28:32.2342||DEBUG|ConfigSample.Controllers.HomeController|Truedbug: ConfigSample.Controllers.HomeController[0]2022-02-21 01:28:32.2342||DEBUG|ConfigSample.Controllers.HomeController|

...    [Route("")]    public string Index()    {...        // key:SampleText1 isn't found in appsettings.json and appsettings.Development.json        var notFound = this.config["SampleText1"];        this.logger.LogDebug($"NotFound Null?:{(notFound == null)} Empty:{(notFound == "")}");        var nullValue = this.config["NullSample"];        this.logger.LogDebug($"NullValue Null?:{(nullValue == null)} Empty:{(nullValue == "")}");        return Json(new Book        {            Id = 1,            Name = "Hello World"        });    }...

dbug: ConfigSample.Controllers.HomeController[0]      NotFound Null?:True Empty:False2022-02-21 01:41:24.1251||DEBUG|ConfigSample.Controllers.HomeController|NotFound Null?:True Empty:False2022-02-21 01:41:24.1459||DEBUG|ConfigSample.Controllers.HomeController|NullValue Null?:False Empty:Truedbug: ConfigSample.Controllers.HomeController[0]      NullValue Null?:False Empty:True

...    [Route("")]    public string Index()    {...        // this return null        this.logger.LogDebug(this.config["SampleArray"]);        return Json(new Book        {            Id = 1,            Name = "Hello World"        });    }...

2022-02-21 02:01:14.6479||DEBUG|ConfigSample.Controllers.HomeController|[null]dbug: ConfigSample.Controllers.HomeController[0]      [null]

...    [Route("")]    public string Index()    {...        var aryList = this.config.GetSection("SampleArray");        foreach(var ary in aryList.AsEnumerable())        {                    this.logger.LogDebug($"Array Key: {ary.Key} Value: {ary.Value}");        }        // I also can get value from the index.        this.logger.LogDebug($"Object {aryList.GetValue(typeof(string), "0")}");        return Json(new Book        {            Id = 1,            Name = "Hello World"        });    }...

dbug: ConfigSample.Controllers.HomeController[0]      Array Key: SampleArray Value:2022-02-21 02:14:59.8252||DEBUG|ConfigSample.Controllers.HomeController|Array Key: SampleArray Value:dbug: ConfigSample.Controllers.HomeController[0]      Array Key: SampleArray:1 Value: World2022-02-21 02:14:59.8435||DEBUG|ConfigSample.Controllers.HomeController|Array Key: SampleArray:1 Value: World2022-02-21 02:14:59.8435||DEBUG|ConfigSample.Controllers.HomeController|Array Key: SampleArray:0 Value: Hellodbug: ConfigSample.Controllers.HomeController[0]      Array Key: SampleArray:0 Value: Hellodbug: ConfigSample.Controllers.HomeController[0]      Object Hello2022-02-21 02:14:59.8474||DEBUG|ConfigSample.Controllers.HomeController|Object Hello

...    [Route("")]    public string Index()    {...        var stringList = new List<string>();        this.config.GetSection("SampleArray").Bind(stringList);        foreach(var ary in stringList)        {                    this.logger.LogDebug($"String Value: {ary}");        }        return Json(new Book        {            Id = 1,            Name = "Hello World"        });    }...

dbug: ConfigSample.Controllers.HomeController[0]      String Value: Hello2022-02-21 02:14:59.8474||DEBUG|ConfigSample.Controllers.HomeController|String Value: Hellodbug: ConfigSample.Controllers.HomeController[0]      String Value: World2022-02-21 02:14:59.8474||DEBUG|ConfigSample.Controllers.HomeController|String Value: World

...    [Route("")]    public string Index()    {...        var sampleBook = this.config.GetSection("SampleBook").Get<Book>();        this.logger.LogDebug($"SampleBook Value: {sampleBook}");        var sampleBooks = new List<Book>();        this.config.GetSection("SampleBooks").Bind(sampleBooks);        foreach(var book in sampleBooks)        {            this.logger.LogDebug($"SampleBooks Value: {book}");        }        return Json(new Book        {            Id = 1,            Name = "Hello World"        });    }...

namespace ConfigSample.Books.Models;public record Book{    public int Id { get; init; }    public string Name { get; init; } = "";    // DON'T DO THIS    public Book(int id, string name)    {        Id = id;        Name = name;    }}

namespace ConfigSample.Books.Models;public record Book{    public int Id { get; init; }    public string Name { get; init; } = "";}

2022-02-21 02:33:55.8597||DEBUG|ConfigSample.Controllers.HomeController|SampleBook Value: Book { Id = 5, Name = Sample }dbug: ConfigSample.Controllers.HomeController[0]      SampleBook Value: Book { Id = 5, Name = Sample }dbug: ConfigSample.Controllers.HomeController[0]      SampleBooks Value: Book { Id = 6, Name = Sample1 }2022-02-21 02:33:55.8768||DEBUG|ConfigSample.Controllers.HomeController|SampleBooks Value: Book { Id = 6, Name = Sample1 }dbug: ConfigSample.Controllers.HomeController[0]      SampleBooks Value: Book { Id = 7, Name = Sample2 }2022-02-21 02:33:55.8768||DEBUG|ConfigSample.Controllers.HomeController|SampleBooks Value: Book { Id = 7, Name = Sample2 }