How does a WinForms .Net sub-application in a solution embed its app.config into itself? - winforms

Question

I am using a variation of Jeff Atwood’s Unhandled Exception handler it steps in when there is an Unhandled Exception in the application. It then logs the error, generates a screen shot and notifies the user.
When compiled in a solution the project generates an EXE that is called when needed. In updating the program I am using Visual Studio 13 to edit the existing settings items in the project properties. In the code I use commands such as this from ConfigurationManager.
string appProduct = unhandledExceptions.Properties.Settings.Default.AppProduct;
I was happy to see that it worked and reflected the changes I made in the IDE. However I couldn’t find the settings in the solutions generated confg file (MyApplication.exe.config). I assumed it was reaching back to the other project folder for the UnhandledExceptions.exe.config.
I created an installer and installed it to a virtual machine. My settings carried over, but again I could not see a config file.
It turns out the values are embedded in the executable UnhandledException.exe.
The project does not have any resources listed. Searching the web and StackOverflow looking a questions that want to do this, and there are a lot of them, it seems this was generally considered not possible and not desirable. Questions usually end in “You don’t want to do that, it’s called config for a reason”.
I may want to turn this off, so it is editable externally. The properties of app.config in both projects are identical.
What setting is making this possible after all? Is it a new capability with Visual Studio 2013?

Answer 1

There is no Visual Studio setting required. If you don’t want the user to have access to the configuration file, don’t include it in the distribution. One can always be added if the settings names are known.
In the description below application generically represents the name of the application being used.
I’ve found through observation some interesting things about the way ConfigurationManager works.
For User settings it will look in the following places in order of priority:
user.config for the application in the user’s AppData area
application.exe.config in the program folder
application.exe itself
Each setting is searched for individually. If your application requests a setting that is not found in either user.config or the application.exe.config it will get it from the executable.
For Application settings it looks in the following places in order of priority:
application.exe.config in the program folder
application.exe itself.
There is no equivalent to user.config for application settings.
Opening the application.exe in the Visual Studio IDE does not reveal a resource for the configuration information.
application.exe.config is handy because it can be modified externally and used as a default value for new installations. Once a setting is overridden in the user.config the value in application.exe.config is ignored.
The same is not true for the AppSettings section, the older configuration method from .Net 1.0. If I delete the configuration file it does not have them in the executable.
These observations were made with Visual Studio 2013 Update 4 and tested in Windows 7 Professional 64-bit. I suspect they are true in all versions.