etiquette - Is it appropriate to drop by another university's professor's lecture to talk about research afterwards?

There is a professor at a university different from the one I study in, who I like to do some research with. I emailed her and did not receive any answer even after sending a follow-up email (a week after the first email). I knew her class schedule, but not her office hours. I thought about going to where the class meets to talk to her after her lecture (introduce myself, try to remind her of the email and express my interest in working with her over and ask her to read my CV that I emailed to her, or arrange some time to meet me and discuss about possible opportunities) .

Since I am not a student at the institution where she works and given the nature of my inquiry and the fact that she didn't answer my emails, I thought this might not be appropriate. I wanted to ask your opinion on whether you think there is a way for me to go and talk to her without it being inappropriate. (I thought about emailing the TA of the class and asking about the office hours of the professor, but I doubt if that's any better.)

Answer

Appropriate should even be, effective less.

You stated you knew her class schedule, so if she is free after the lesson you may have success to speak with or, better, to ask her when she can dedicate you some minutes.
It can be appropriate if you will be polite, clear, specific and concise.

E.g. I need 5-10 minutes to speak about xxx. I read those papers of yours (a,b), I find interesting yyy and I would like to work on it maybe in the zzz development. I'm currently student/phd/whatever in the ttt university. Is there any way to arrive to work on this subject with your group? What can I do?

There are, by the way, other ways in which you can contact her.

Secretary of the group or of the department. Each professor belong to group(s) and/or department(s). Find which, and call the secretary. (Again concise). Ask how to contact that professor.

Conference or Talk. If you have the time and the occasion it may be more effective if you find an open event in which to meet, e.g. if she takes part on a conference, or she has a talk accessible for you. In those occasions people is usually more open, and has already reserved time to speak.

Professor of your university of the same field. If you can access to some professor actually enrolled in your university in the same field of the one you want to contact, you may ask him/her information about that professor and how to contact. If they personally know each other, you can ask to be introduced too, or at least to send her a mail.

Her Office. Knock the door and ask when she has some time to speak with you about xxx...

ps> She may have some time to dedicate to students... you may try to go in that time, but you will be after the needs of her students.