Private Const strSomeTagName As String = "AlreadySubscribed"
Private Sub cel_InstrumentSubscribed(ByVal Symbl As String, _
                                        ByVal Instrument As CQG.ICQGInstrument)
    If Instrument.Tag(strSomeTagName) = True Then
       ' Instrument was already subscribed once
    Else
       Instrument.Tag(strSomeTagName) = True
       ' Instrument subscribed first time
    End If
    ' Here we tell CQGCEL to send us ask/bid change notifications along
    ' with quote changes
    Instrument.DataSubscriptionLevel = dsQuotesAndBBA
    Range("B5") = Symbl
    Range("B6") = Instrument.Description
    Range("B7") = Instrument.YearString
    Range("C7") = Instrument.MonthChar
End Sub
Private Sub cel_IncorrectSymbol(ByVal Symbl As String)
    ' Incorrect symbol (Symbl) is passed to NewInstrument function
End Sub

const string strSomeTagName = "AlreadySubscribed" ;
 
private void cel_InstrumentSubscribed(string Symbl, CQGInstrument Instrument)
{
    if( Instrument == null )
    {
        // Failed to subscribe instrument
        return ;
    }
    
    if( Instrument.get_Tag( strSomeTagName ) == true )
    {
       // Instrument was already subscribed once
    }
    else
    {
       Instrument.set_Tag( strSomeTagName , true ) ;
       // Instrument subscribed first time
    }
    // Here we tell CQGCEL to send us ask/bid change notifications along
    // with quote changes
    Instrument.DataSubscriptionLevel = eDataSubscriptionLevel.dsQuotesAndBBA ;
    Console.WriteLine( Symbl ) ;
    Console.WriteLine( Instrument.Description ) ;
    Console.WriteLine( Instrument.YearString ) ;
    Console.WriteLine( Instrument.MonthChar ) ;
}
 
private void cel_IncorrectSymbol(string Symbl)
{
    // Incorrect symbol (Symbl) is passed to NewInstrument function
}