you say you've tried lots of things... but how long for? IME you have to be consistent. don't just try ignoring for an afternoon... do it for a couple of days.
if he throws something then say NO to him, loudly and firmly, in your most serious (scary) voice.
then put whatever it was back.
you have to keep on and on and on with the same approach. if you see him about to throw something don't cajole him or try to reason with himn... he is too little and he enjoys the attention.
again just say no, and take it from him.