Porting System.Configuration to .NET Core via POCOs?

Question

We've got a .NET Framework .dll that we're porting to .NET Core. Currently we're inheriting from ConfigurationElement and ConfigurationSection from System.Configuration to create custom configuration sections in the app.config (or it's .NET Core equivalent)

Questions:

1. It appears the .NET Core way is Microsoft.Extensions.Configuration. Is that correct? Because it lives on ASP.NET Core's github project instead of .NET Core's github project. We have no ASP parts.

2. If so, any .NET Core examples on creating and loading custom configuration sections not relying on startup.cs ? Ideally we'd like to read from a text source (XML or JSON) directly into a POCO object graph for strongly typed benefits.

3. With .NET Core 2.0, will there be any support for the traditional ConfigurationElement and ConfigurationSection negating the need for any such porting efforts to begin with ? Reason I ask is the .NET Core 2.0 Roadmap says

   .NET Core gain over 5,000 APIs from .NET Framework as part of this work making it a broader platform.

Answer 1

I am not aware of app.config and System.Configuration support in .NET Core. Probably, no, but that's just a guess. You can setup configuration for .NET Core application in Main method:

class Program
{
    static void Main(string[] args)
    {
        var configuration = new ConfigurationBuilder()
            .AddJsonFile("appsettings.json")
            .Build();

        var poco = new Poco();
        configuration.Bind(poco);

        Console.WriteLine(poco);
        Console.ReadKey();
    }
}

class Poco
{
    public bool Enabled { get; set; }
    public Sort Sort { get; set; }

    public override string ToString()
    {
        return $"Enabled={Enabled}, SortOrder={Sort.Order}";
    }
}

class Sort
{
    public int Order { get; set; }
}

appsettings.json is following:

{
  "enabled": true,
  "sort": {
    "order": 2
  }
}

Outputs:

Enabled=True, SortOrder=2

You need to reference Microsoft.Extensions.Configuration.Json and Microsoft.Extensions.Configuration.Binder packages.

No dependency on ASP.NET Core.

Microsoft.Extensions.Configuration is quite extensible, it can use different settings providers like environment variables, command line arguments, etc. So it is possible to implement custom provider for ConfigurationSection-like configuration if needed.

Based on this comment they are not going to bring System.Configuration to NetStandard 2.0.