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.)
I would not appreciate that. I have a schedule, which means that after a lecture I may have a meeting, I may have an appointment with someone I am supervising, I may need to pick up my children from day-care, etc. etc. etc.

If you have emailed twice and not received an answer, then that is your answer... That is not very polite, but none of us are perfect.