How Can You Catch A Darkrai Without An Event On Pokemon Platinum?

Yes you can but with action replay I don't know where to buy action replay for ds you also need a code for the action replay but the problem is if you activate to many codes on to ds you might damage your game so don't activate  to many codes ! You can also ask what is the code for catching darkrai and how to activate that code I'm sorry that I can't find out this code or how to activate. Hoped I helped