Hundreds of leash-wielding New Canaan and area animal lovers descended on the parking lot at Pet Pantry on Grove Street on Sunday for a dog-friendly event that’s become a hugely popular spring tradition downtown. Less than halfway through the 7th Annual New Canaan Dog Days, an estimated 500-plus dog-lovers had visited the merchant tents, signed their four-legged family members up for contests, sampled free ice cream from Baskin Robbins and enjoyed the music of New Canaan School of Rock, one of its organizers said. As it did for Caffeine & Carburetors at Waveny in the morning, the weather held out for Dog Days, said Adam Jacobson, executive vice president of Pet Pantry New Canaan. The event is expected to raise “thousands upon thousands of dollars” for Adopt-A-Dog as well as Strays & Others, Jacobson said. “We have great support from our vendor partners,” including New Canaan Veterinary Hospital, he said.