ConfigurationManager In WPF
Answer : Just add an app.config and not web.config because it is not a web application. And after that it's too simple, just add a reference to to System.Configuration and then use this. var ConnStr = ConfigurationManager.AppSettings["Trackboard"]; I've figured it out! I shouldn't have created a new config file. There is a default app.config file in the project. Now everything is fine. <?xml version="1.0" encoding="utf-8" ?> <configuration> <configSections> </configSections> <connectionStrings> <add name="Trackboard.Properties.Settings.TrackboardConnectionString" connectionString="Data Source=(LocalDB)\v11.0;AttachDbFilename=|DataDirectory|\DATABASE\Trackboard.mdf;Integrated Security=True" providerName="System.Data.SqlClient" /> </connectionStrings> </configuration> private static string ConnStr = ConfigurationMana...