[itsCody]

pawn Код:

#define DIALOG_MSGBOX 999
CMD:showplayers(playerid, params[])
{
    new playercount, string[128];

    foreach(new i : Player)
    {
        format(string, sizeof(string), "%s%i) %s[%i]\n", string, ++playercount, PlayerName(i), i);
    }
    
    if(!playercount)
    {
        ShowPlayerDialog(playerid, DIALOG_MSGBOX, DIALOG_STYLE_MSGBOX, "Online Players", "There are no players online", "OK", "");
        return 1;
    }

    else ShowPlayerDialog(playerid, DIALOG_MSGBOX, DIALOG_STYLE_MSGBOX, "Online players", string, "OK", "");
    return 1;
}

untested but it should work