I find it easier not to have those kinds of foods in the house at all. FWIW, I do it eat dark chocolate several times a week (at least 70% Cacao). I find that I am able to eat about a hundred calorie portion without eating more. I'm not sure why that is, maybe because it isn't very sweet.
But, there are some foods (cookies for example) that I just don't have in the house since I find them hard to control...