C# void

Hi! I'm a beginner at c# and was wondering how to save a variable that changed after a button click.
I mean the buttons are void type so they don;t return anything and the values changed in there don't change globally, so let's say I have a Boolean variable C that after a button click becomes true, how do I save that so I could use it within another button click?

http://en.wikipedia.org/wiki/Scope_(computer_science)

Most importantly, also read about variables extents.

Where do these retards come from?