Mayor Vincent C. Gray welcomed about 1,800 District residents to the Walter E. Washington Convention Center on Saturday for a citizens summit — an event praised for engaging the public but criticized for its $600,000 price tag and seeming bureaucracy.

Grouped at numbered tables as if at a banquet, participants prioritized the city’s issues, ranking the lack of affordable housing and corruption first and second, respectively. They also discussed ways to improve public education, create jobs and even dispose of vacant city property.

Using wireless devices smaller than calculators, participants voted on the priorities and ideas with results appearing immediately on large screens.

“This is real-time, grass-roots democracy, D.C. style,” Gray (D) told the crowd.

But some participants questioned whether their ideas would be implemented while others wondered whether the “One City Summit” was stuck in the past even as it used high-tech devices and was streamed live online.

Carolyn J. Lukensmeyer, founder and president of America Speaks, the nonprofit that facilitated the summit, told participants that electronic devices and tweeting were prohibited when the event began in the morning. The announcement drew outrage from Twitter users inside and outside the event, and the decision was reversed.

The “One City Summit” came days after Gray delivered his State of the District address, marking a week of public relations moves for a mayor who spent his first year in office trying to repair missteps made during his initial months.

Gray’s administration acknowledged the summit was a throwback to the administration of former mayor Anthony A. Williams, a two-term mayor who often had to fight the perception that he was aloof. Williams held four similar events, also facilitated by America Speaks, while in office. In 1999, at his first summit, Williams wore a plaid shirt and khakis, an everyman’s outfit. Gray appeared Saturday in a sports jacket and tieless.

Though the event revived a Williams policy, it also seemed to acknowledge Gray’s predecessor Adrian M. Fenty, whose 2010 defeat was attributed partly to losing touch with constituents and failing to listen to them. Fenty conducted no such summits, holding his annual State of the District addresses during the day and at small venues.

In contrast, the Gray administration poured $600,000 into Saturday’s summit, paying America Speaks $480,000 and getting sponsors to pick up $50,000, said Pedro Ribeiro, Gray’s director of communications. A speechwriter was hired to help with the mayor’s address, costing up to $5,000.

“This is another big reset opportunity for the mayor,” said Sylvia Brown, an advisory neighborhood commissioner from Ward 7.

It was similar to the Ward 8 Community Summit held in July, she said. That event, also facilitated by America Speaks, cost about $200,000; that was offset by a grant from the U.S. Department of Housing and Urban Development, said Victor L. Hoskins, deputy mayor for Planning and Economic Development.

“This is good for people who are not engaged on a regular basis,” Brown said.

David Camero, a 49-year-old who teaches art workshops, said he learned of the summit while participating in a CPR class for Latinos last week.

“This was nice of the mayor,” he said. “It’s important to know the different ideas and share how we can help.”

By the end of the day, 72 percent of participants said their satisfaction with the summit was high or very high, according to an instant poll. According to other surveys during the event, a majority of the participants at the convention center were women and 60 percent were at least 45.

Other participants and some residents who showed up at the convention center to protest found the summit too structured. America Speaks representatives and Cabinet members from the Gray administration set the day’s agenda, carefully ushering the discussion along.

Daniel del Pielago, an organizer with Empower DC, a grass-roots organization currently focused on affordable housing and stopping school closures, said he was prohibited from distributing leaflets inside the event. A protester, who was not affiliated with Empower DC, was escorted out after he tried to display a banner reading “Jobs, Not Jails.”

“Affordable housing for all,” the man yelled as he was led out.

“To me, it’s explicit the way they want to shape the conversation,” said del Pielago, a Ward 1 resident. “These are foregone conclusions, what they want to talk about.”