AppSettings in App or Web Config Using a Linked File

In the Web.Config you must add "bin/" (se example below).

By default the web.config is NOT copied into the bin folder but the file common.config is, therefore you must add the path from web.config. In a non-web project the default behavior is that the App.config is copied to the bin folder with name MyProgram.exe.config and is in the same directory as common.config.

<appSettings file="bin/common.config">