There are no "Cheats" for pokemon. Only hacking tools or glitches like cloning, action replay codes etc.
You are going to have to either use a cheat or catch it with a Master ball.
trade a friend a pokemon and his pokemon holding a master ball
In Pokemon Diamond, Pearl and Platinum you can get one master ball from Master Cyrus. To get more, you have to cheat using a Action Replay DS or DSI, or you can trade Pokemon with your friends and receive master balls from the Pokemon that they traded.
master ball
no
you can not get a master ball in Pokemon platinum only the one professor Rowan gives you
Um Who told you that cheat is probably a lair but it is true for the 999X master ball cheat.
with a master ball or timer ball
there is no more masterballs in Pokemon platinum but not if you use cheats
with a master ball
Master Ball.
After defeating Cyrus in Veilstone, he should give a Master Ball to you.