How to use a App.config file in WPF applications?

Question

I created an App.config file in my WPF application:

Answer 1

You have to reference the System.Configuration assembly which is in GAC.

Use of ConfigurationManager is not WPF-specific: it is the privileged way to access configuration information for any type of application.

Please see Microsoft Docs - ConfigurationManager Class for further info.

Answer 2

This also works

WpfApplication1.Properties.Settings.Default["appsetting"].ToString()