App config in a reference dll

Hi,

 I am using .net core 2.0 and calling a dll which is written in VS 2008. The dll refer its app config file to get some values.

Since I am calling the method from .net core it is looking for the config values from VS 2017 preview 2.

Could you please tell me how to assign the values in the appsettings.json

Regards,

N.ShanthaKumar.