Betrayal at work...how did you handle it?

I've been around the block, but not jaded enough to distrust everyone at work. This woman and I have become close colleagues in a corporate environment that is mostly men. We've known each other for 2-3 years now. I don't need to go into the detail of the betrayal, but she's done it twice. Nothing significant enough for me to cut off all ties, but enough to show me her character. Last time she put me on the spot in a meeting in front of the senior executives. Her statement had nothing to do with the work, but everything to do with her trying to look forceful and all-knowig. I expected that from other people, but not from "a friend". It's very disappointing and hurtful. My theory is people don't change. I have written her off as a true friend at this point, so to me, there is nothin gain from confronting her. How have you handled something like this?