Here is the summary of what happened via Reuters:

Thousands of protesters who showed up for Trump’s rally Friday evening at the University of Illinois at Chicago – along with thousands of supporters – showed little indication they had noticed anything but the candidate’s combative campaign style. The university arena turned into a chaotic scene as the two warring sides amped up their positions. A half hour after the rally was slated to begin, a Trump campaign staffer announced it was being postponed for safety reasons, unleashing competing chants of “We dumped Trump!” and “We want Trump!” throughout the packed venue.

“We made a great decision not to have the rally,” Trump told CNN after meeting with law enforcement and making the call. “I am not a person that wants to see violence,” he added.

Trump blamed protesters for creating disturbances at his campaign events and said it is a “love fest” among his supporters.

Friday’s event in Chicago stood out because the huge number of protesters virtually matched the number of Trump supporters, as opposed to other Trump campaign events where protesters have been a very small, albeit vocal, minority.

Earlier in the day, speaking at a public event in St. Louis, Missouri, Trump was interrupted repeatedly by protesters who were led out of the event by police and security, an increasingly common occurrence at his raucous rallies. “He’s all mouth, get him out,” Trump shouted as one of the protesters was led out. “Go back to mommy,” he said as another protester was led away.

more at Source: Trump Cancels Chicago Speech After Violent “Make America Hate Again” Protests Erupt | Zero Hedge