[Mean]

This is how to show it in chat, you can just convert it to dialog:
ALSO USING ZCMD

pawn Код:

CMD:onlineplayers( playerid, params[ ] ) 
{
    new count = 0;
    for( new i; i < MAX_PLAYERS; 1++ )
    {
        if( IsPlayerConnected( i ) )
        {
            count++;
            new string[ 128 ];
            new pName[ 24 ];
            GetPlayerName( i, pName, 24 );
            format( string, sizeof string, "[%d.] %s", count, pName );
            SendClientMessage( playerid, 0xAAAAAA, string );
        }
    }
    return 1;
}

Too lazy to write a code for dialog now...