使用强类型重新加载 appsettings.json

Question

This is my appsettings.json

{
  "MySettings": {
    "DefaultSetting": "Key1",
    "Settings": {
      "Key1": {
        "Full": "Description1",
        "Short": "Desc1"
      },
      "Key2": {
        "Full": "Description2",
        "Short": "Desc2"
      },
      "Key3": {
        "Full": "Description3",
        "Short": "Desc3"
      }
    }
  }
}

My Class defined:

public class MySettings
{
  public Dictionary<string, Setting> Settings { get; set; }
  public string DefaultSetting { get; set; }
}
    
public class Setting
{
  public string Full { get; set; }
  public string Short { get; set; }
}

My Startup.cs :

public void ConfigureServices(IServiceCollection services)
{
  // Add framework services.
  services.AddApplicationInsightsTelemetry(Configuration);
  services.Configure<MySettings>(Configuration.GetSection("MySettings"));
  services.AddMvc();
}

In HomeController:

public class HomeController : Controller
{
  private readonly MySettings _mySettings;
  public HomeController(IOptionsSnapshot<MySettings> mySettings)
  {
    this._mySettings= mySettings.Value;
  }
    
  public IActionResult Index()
  {
    return Json(_mySettings.DefaultSetting);
  }
}

I want to get the new setting values when I save the changed appsettings.json file and refresh my browser.

I have tried the IOptionsMonitor before

Here is the reference .

But I have many strongly typed classes, it will register too many IOptionsMonitor .

Is there an easier way to implement auto reload strongly typed class?

Answer 1

Yes, you can reload appsettings on change. To do this, in startup constructor, assign reloadOnChange to true like this-

    var builder = new ConfigurationBuilder()
        .SetBasePath(env.ContentRootPath)
        .AddJsonFile("appsettings.json", optional: true, reloadOnChange: true)
        .AddJsonFile($"appsettings.{env.EnvironmentName}.json", optional: true, reloadOnChange: true)
        .AddEnvironmentVariables();