How to programatically update custom attribute in app config file

Question

My app.config.

 <?xml version="1.0" encoding="utf-8"?>
    <configuration>
      <configSections>
      </configSections>
      <Something SettingsLocation="D:\test\test\file.json" />
      <Something />
      </configuration>

I need to update SettingsLocation programatically. I found this some answers, but it is not clear to me. Thanks fo help.

Answer 1

Each application has it’s own configuration file, be it a windows based application or web based. This application configuration file defines information which can be used by application to make decisions, to load some other information or may contain the custom configuration which can be empowered to do anything. There can also be scenarios where an application may want to change\modify the existing setting in the application configuration file and those changes should not only take effect immediately but should also be persisted.

Possible solution is already shown here