Mein Versuch

    if(strcmp("/carkey", cmdtext, true) == 0)
    {
        new string2212[256];
        for(new i=0; i<MAX_PLAYERS;i++)
        {
            for(new x=0;x<MaxVeh;x++)
            {
                format(string2212, sizeof(string2212), "%d %s\n%d %s\n%d %s\n%d %s\%d %s",Dtc_PlayerKey[playerid],CarName[PlayerCar[x][Dtc_PlayerKey[x]][CarModel]-400]);
                ShowPlayerDialog(playerid, DIALOG_CARKEY, DIALOG_STYLE_LIST, "{FF0000}Deine Schlüssel",string2212, "Auswählen", "Abbrechen");
            }
        }
        return 1;
    }