
I agree with Livingdustmops and FirstYorkie---Positive reinforcement in the form of treats and praise is very powerful and effective. And there's nothing wrong with it. It is a great way to let your Yorkie know that he is doing what you want him to do.
Remember, your Yorkie WANTS to please you. Dogs are pack animals, and as long as you are percieved as the pack leader, he wants to do what you want him to do. Communicating what you want is generally where the problem arises.....treats and praise are a great way of communicating that he is doing the right thing.