And you also said "you will be turned around if you try to cross", referring to the OP who hasn't been convicted.
My point is that until the outcome of his case, the OP can still travel to Canada.
It is not worth taking the risk because you can be asked "have you ever been arrested?" And yes Customs and Immigration can find that out. Simply for a DUI even though the case hasn't been to court yet, they can refuse you entry just for being arrested. I read an article not to long ago where the person was charged but not found guilty of a DUI and Canada refused this person entry. I grew up on the Canadian/American border and it was closer for me to cross into the US for gas and food then to go to my next town. I would cross 150 times a year times 28+ years. Some of it was personal and other was business because I drove tractor trailer. When it comes to Canadian Customs and Immigration, I am quite versed in that subject. Remember it is all up to the border guard.