title: Changing color of a line in a multiline textbox if the line begins with a specific character?
body: <p>So long story short, I'd like to make it so that if a line in a multiline textbox beings with 
  '!' it makes the line color red. Otherwise, it remains black. </p>
  
  <p>Sounds simple with an if statement, but I can't seem to figure out what exactly to do. Is such a thing possible?</p>
  
  <p>I'm using C#.
  *To clarify, I would like it to do it automatically, not needing a button to be pressed.</p>