The MSBuild project file (.csproj) is an xml file that describe and control the process of generation of the applications. The path to the acad.exe file of the AutoCAD version to be launched at ...

If you are adding an application configuration file to a C# or Visual Basic project, then you should name it App.config rather than appName.exe.config, and the item type should be None or Content.

The C# code when the look at the app.config during runtime to grab the proper datasouce. What I have found is that this is easy to do with an .EXE file but apparently a lot messier using a DLL.