Daisy7 / Rena, your blackcurrant won't need canes, it will support itself. The raspberry will grow thin canes 3 - 4 feet long and if you don't support them they flop over. Although I find it's an advantage to let the canes flop a little bit as the fruits are then hidden under the leaves and the birds don't see them. If you only have one plant you can put in bamboo canes and tie each rasperry cane in separately. If you have a row of rasps you can put in 2 strong supports at each end,of the row, one each side, and attach strings along the length of the row, one each side, so the raspberry canes are supported inside them.
Don't know if that made sense, someone else might have a picture to illustrate it.