We caught 2 of our semi-feral barn cats by using food and a dog cage. After feeding daily for a while near an open dog cage , we then began to move the dish closer to the cage every day or so, eventually putting it right on the edge inside the open door.
After a week of doing that, we moved the bowl deeper inside until it was against the back wall. Then, when we could, we slammed the door and took the cat to the vet for the local Catch/Neuter/Release program. I thought for sure they'd never come back to the house after that treatment, but they did as if nothing had happened!
Food is a major incentive, ask me how I know, LOL!
Jan in VA