To be honest, all your attempts at "getting round" what you see as a problem are ugly, inefficient, and unnecessary - and would almost certainly fail code reviews everywhere I've seen.
And make your code look "student grade" at the same time!
If you can't "see" the exclamation mark, then increase the font size of your IDE - "!" is quite large and visible compared to ".", ",", "^", and "~" for example, and missing any of them would make your code even harder to read.
if (!int.TryParse(userInput, out qtyOfCheese))
Is pretty standard code!