GUANGZHOU, China  The mood of participants here at the world’s largest trade show on Thursday depended largely on how they were being affected by the weak American dollar.

As throngs of prospective buyers swarmed the exhibitions, equal to five times the floor space of the Empire State Building, Chinese exporters were upbeat. By keeping China’s currency, the renminbi, tightly yoked to the weak and weakening dollar, Beijing had made Chinese exports increasingly competitive around the world.

“We are very confident,” said Liu En Tian, the marketing manager of the Huasheng Jiangquan Group, a manufacturer of ceramic tiles in Linyi City. “Already the buyers who are coming this morning are more than last year.”

Like those of many Chinese manufacturers, his company’s exports fell by nearly half last winter because of the global economic slowdown, but they are now down only 20 percent from their peak more than a year ago because of a surge in sales to South America and the Middle East. “The economy will get better very soon” around the world, Mr. Liu said.