Answer by Dmitry Grinko for Reading settings from app.config or web.config in .NET

I'm using Visual Studio for Mac version 17.0.6.

As you can see on this screenshot it is not possible to add a reference to System.Configuration.

Solution:

1. install NuGet Package - System.Configuration.ConfigurationManager.
2. Create app.config file and set "Build action" to "EmbeddedResource"

<?xml version="1.0" encoding="utf-8"?><configuration><appSettings><add key="name" value="Joe"/></appSettings></configuration>

3. using System.Configuration;
4. enjoy)

string name = ConfigurationManager.AppSettings["name"];

BTW: Do not add an app.config for a library