@Dipta and others,
well it's country and college vs. Uni basis. Like in India, you need to pay at least one semester fee in order to apply for visa and not to forget, if applying under SPP also need to purchase GIC for 10k CAD.
For applicants from Pakistan, they needn't pay fee in advance before they get the visa.
for applicants even from India, some Uni recommend not to pay the fee before the Visa. Hence, it's case to case basis.
and I think (not too sure) for china as well, you get the visa first and then pay the fee.
Cheers!