Are food and drinks allowed in the building during events? Or will I be asked to throw it away?

In the building...yes. In the hallways outside the exhibit halls...yes. possibly not allowed once in the exhibit hall

This is dependent on the conference or event.

Yes Jon Goetz is correct.

They don't allow out side drinks into the auditoriums unless they are covered. So no cans or cups without lids but coffee cup with lids and water bottles are ok.

Agree with Jon Goetz. Coffee shop and vending machine in the main hall area.