title: How to use System.Configuration.ConfigurationManager in .netstanard library for .net core and .netframework
body: <p>I am migrating the .netframework 4.7.2 class library to .netstandard 2.0 library. </p>
  
  <p>ConfigurationManager is used in the .netframework class library to read the app settings. </p>
  
  <p>Any alternative option available for the System.Configuration.ConfigurationManager in .netstanard. </p>
  
  <p>The migrated class library needs to be used in a .net core web API and old .netframework web application.  </p>