如何使用 class 库读取 appsetting.json 或 App.config？ json 和配置文件都在同一个 class 库项目中

Question

So here is the scenario.

I am developing some independent tool so i am working with class library. Now i want to save some information into same project which is class library. I tried with appsetting.json and App.config but it only works in web project.

My project looks like below

i tried below code

var id = System.Configuration.ConfigurationManager.AppSettings["client_id"];

but it is not working. if i put that same file in web project it is reading successfully.

In my case config/json file must be in class library and must read from itself

Answer 1

In a .net core application you need to use Dependency Injection to inject IConfiguration into your class which will expose your appsettings json values:

public class Foo
{
    private IConfiguration _config { get; set; }
    public Foo(IConfiguration config)
    {
        this._config = config;
    }
}

Now you can read settings:

    public void DoBar()
    {
        var id = _config.GetSection("client_id").Value;
    }

Just keep chaining .GetSection() to move down your hierarchy.

Answer 2

I found a soultion to this problem.

You can add Resource.resx from property window of class library.

here are the screen shots.

and then use code as below

using AdobeSign.Properties;

var id = Resources.client_id.ToString();

Answer 3

If you want to have config.json in your class library separately, I recommend that you define your configuration model and implement deserialization for the file.

let's just assume your config.json content is like,

{ "MyValue1": "Hello", "MyValue2": "World" }

you can define Configuration class like below,

using Newtonsoft.Json;
using System;
using System.IO;

namespace Example
{
    public class Configuration
    {
        public string MyValue1 { get; set; }
        public string MyValue2 { get; set; }

        public static Configuration Load(string path)
        {
            if (File.Exists(path))
            {
                var json = File.ReadAllText(path);
                return JsonConvert.DeserializeObject<Configuration>(json);
            }
            else
            {
                throw new Exception("Configuration file not found!");
            }
        }
    }
}

then you can load your config object from the file and use it like below,

var config = Configuration.Load(Path.Combine(Directory.GetCurrentDirectory(), "config.json"));
Console.Write(config.MyValue1);
Console.Write(config.MyValue2);