What is the action replay code to be able to capture trainers in "Pokemon Diamond"?

You can capture an opponent's Pokémon by pressing L + R while using an Action Replay and entering one of the following codes: 9223b5fa, 00002101, 00002100, D2000000 or 1223b5fa. This often catches the trainer's first Pokémon, not their current one, and ends the battle.

Action Replay has been around since the Commodore 64 and has continued all the way up to the Nintendo 3DS and Wii consoles. Action Replay codes typically allow players to gain things like infinite lives, instant kills, warp to any level, super high jumps or gain items not normally obtainable. They also allow players to download, import or export saved files.