Yes, I and my husband went to Accra for the interview. The visa officer asked him (he is the applicant) about my life in Canada - my family, my job, where I lived, my hobbies, my friends, my past relationships, etc. She also wanted to know what he knew about Canada, and specifically what he knew about Saskatoon (where I live). She then went through the immigration application and asked him the same questions that were on the forms, including things like "How many brothers and sisters do you have?" She seemed to be looking for any contradiction between what we wrote on the forms and what he said at the interview. She kept on asking him why he married me.
I went to the embassy with him and was waiting outside, so when the visa officer found out I was there, she called me in and interview me as well. She asked me about how we met and the development of our relationship. She kept on asking me how I knew he wouldn't just run away as soon as he got to Canada.
Basically, your wife should know the details that were written in the forms and be able to give the same answers. They are looking for contradictions. She should know a lot about your life in Canada - your job, home, the town you live in, your friends, what you do in your spare time. She should be able to give an account of how your relationship progressed.
