[amirab]

This can help you put these codes in OnPlayerConnect or after register or any thing you want :

PHP код:

            new sendername[MAX_PLAYER_NAME];
            GetPlayerName(playerid, sendername, sizeof(sendername));
            new namestring = strfind(sendername, "_", true);
            if(namestring == -1)
            {
                SendClientMessage(playerid, COLOR_YELLOW, "Your name must be in the Firstname_Lastname format - Please re-log with a name such as Amir_AB");
                Kick(playerid);
                return 1;
            }