Retrieve configuration from appsettings.json

Question

ASP.NET Core now uses appsettings.json for the application configuration, i just want to get the connection strings from the following appsettings.json file:

{
  "Logging": {
    "IncludeScopes": false,
    "LogLevel": {
      "Default": "Debug",
      "System": "Information",
      "Microsoft": "Information"
    }
  },
  "ConnectionStrings": {
    "Default": "Server=localhost; Database=mydatabase; Trusted_Connection=True;User id=myuser;Password=mypass;Integrated Security=SSPI;"
  }
}

That's the only value the I need to get in my controllers. Do I really need to create a class for it?

Answer 1

No, you don't have to create a class for it. You can simply use IConfiguration to access ConnectionStrings . Simple usage:

public class Startup
{
    private IConfiguration Configuration;

    public Startup(IHostingEnvironment env)
    {
        var builder = new ConfigurationBuilder()
           //...;
        Configuration = builder.Build();

        // Get ConnectionString by name
        var defaultConStr = Configuration.GetConnectionString("Default");
    }
    // If you need to resolve IConfiguration in anywhere with dependency injection, below code is required
    public void ConfigureServices(IServiceCollection services)
    {
        services.AddSingleton<IConfiguration>(Configuration);
    }

}

Update for comment

public class YourController : Controller
{
    private readonly IConfiguration _config;
    public YourController(IConfiguration config)
    {
        _config = config;
    }
}