grammar - Understanding これといった〜ない

I was playing a game (Yu-Gi-Oh) until I found this:

これといった用があって来たわけじゃない.

This was in the very beginning of the game, when someone woke me up. I'm not sure what 「これといった」and 「わけじゃない」mean. May someone help me, explaining the sentence? Thank you very much!