Mr. Darcy danced only once with Mrs. Hurst and once with Miss Bingley, declined being introduced to any other lady, and spent the rest of the evening in walking about the room, speaking occasionally to one of his own party. (Ch. 3)

Darcy may well have been introduced to any number of men but did not linger to converse with any of them. Certainly we know Darcy was standoffish and more likely to listen in on conversations than participate; we see this at the Lucas party and even as late as his visits to Hunsford. This is just the behavior he described at the Rosings piano.

"I certainly have not the talent which some people possess," said Darcy, "of conversing easily with those I have never seen before. I cannot catch their tone of conversation, or appear interested in their concerns, as I often see done." (Ch. 31)