A seldom used feature of dotnet config files is the possibility to link to another file. Use configSource=”theotherfile” or file=”theotherfile” as attribute. An example and comments are found here.
This is old news indeed but every time I use it I tend to google for a while since I cannot remember the keywords.
Example of use:
I have an ordinary app.config file. It links to connectionstrings.config which keeps my <drumroll/> development connection string. For creating an installation file I have a normal setup/installation project. This project takes the file connectionstrings.prod.config and incorporates it in the MSI while renaming it to connectionstrings.config.