I want to add Tom to the answer .
He's right, ClickOnce only cares about the publication version for the project. However, as soon as your application runs on the client machine and it recognizes its not the latest version, it starts comparing the hash files from the application manifest (the application manifest is one that does not have the extension β.applicationβ ... go figure), therefore it loads only files that have been modified; yes, recompiling without changing the code is still a change.
And one last point. The progress bar that appears when the client downloads the latest version always shows the full size of your application. However, be sure that this is only downloading modified files. I checked with a bandwidth monitor to confirm it.
source share