If I have a retail fraud charge, will that mean I cannot travel to Canada?

Being denied admission into Canada is a good possibility since the Canadian gov't is very strict about allowing anyone with a criminal record into the country. I doubt that you would be arrested, but you may be asked to turn around and return to the U.S.

Whether you can be allowed to enter Canada will depend on Canadian immigration law and as such you need to consult with a Canadian immigration lawyer. However, I must advise that like the United States a person who is convicted of a crime constituting a crime of moral turpitude are generally deemed inadmissible and if so, may enter Canada by applying for a waiver. Also note that unless you are a US citizen, your travel to Canada after conviction for a crime involving moral turpitude may render you inadmissible to return to the United States.