Option Explicit
' CQGCEL instance declaration
Public WithEvents cel As CQGCEL
Private Sub Workbook_Open()
    ' Initialize CQGCEL instance.
    On Error Goto ErrHandler
    Set cel = New CQGCEL
    cel.Startup
   
    Exit Sub
ErrHandler:
    If Err.Number <> 0 Then
        MsgBox "Error occurred during CEL initialization. " & _
                Err.Description
    End If
End Sub
Private Sub Workbook_BeforeClose(Cancel As Boolean)
    ' Shutdown the CQGCEL instance.
    cel.Shutdown
End Sub
Private Sub CEL_CELStarted()
    ' Create new instrument after CEL is started up
    cel.NewInstrument "DD"
End Sub
' START of CQGCEL event handlers.
Private Sub cel_InstrumentChanged(ByVal Instrument As CQG.ICQGInstrument, _
                                    ByVal Quotes As CQG.ICQGQuotes, _
                                    ByVal Props As CQG.ICQGInstrumentProperties)
    ' You'll get here if "DD" Instrument data is changed.
    cel.Logger.Log "Instrument Data Changed : " & Instrument.FullName, lsInfo
End Sub
Private Sub cel_InstrumentSubscribed(ByVal Symbl As String, ByVal Instrument As CQG.ICQGInstrument)
    ' You'll get here if "DD" Instrument is subscribed.
    cel.Logger.Log "Instrument Data Changed : " & Symbl, lsInfo
End Sub
Private Sub cel_IncorrectSymbol(ByVal Symbl As String)
    ' You'll get here if "DD" Instrument is not subscribed.
    cel.Logger.Log "INCORRECT SYMBOL: " & Symbl, lsError
End Sub
Private Sub cel_IsReady(ReadyStatus As CQG.eReadyStatus)
    ' CQGCEL asks Excel whether it's ready for event processing.
    ReadyStatus = IIf(Application.Ready, rsReady, rsNotReady)
End Sub
Private Sub cel_DataError(ByVal Obj As Object, ByVal ErrorDescription As String)
    cel.Logger.Log "ERROR : " & ErrorDescription, lsError
End Sub
' END of CQGCEL event handlers.

using System ;
using CQG ;
using System.Runtime.InteropServices ;
namespace Sample
{
   class TestCQGCEL
   {
      // CQGCEL instance declaration.
      public CQGCEL cel = null ;
      public TestCQGCEL()
      {
         // Initialize CQGCEL instance.
         try
         {
            cel = new CQGCEL() ;
            // Attach event handlers.
            cel.InstrumentChanged += new _ICQGCELEvents_InstrumentChangedEventHandler( cel_InstrumentChanged ) ;
            cel.InstrumentSubscribed += new _ICQGCELEvents_InstrumentSubscribedEventHandler( cel_InstrumentSubscribed ) ;
            cel.IncorrectSymbol += new _ICQGCELEvents_IncorrectSymbolEventHandler( cel_IncorrectSymbol ) ;
            cel.CELStarted += new _ICQGCELEvents_CELStartedEventHandler( cel_CELStarted ) ;
            cel.IsReady += new _ICQGCELEvents_IsReadyEventHandler( cel_IsReady ) ;
            cel.DataError += new _ICQGCELEvents_DataErrorEventHandler( cel_DataError ) ;
            cel.Startup() ;
         }
         catch( COMException ex )
         {
            Console.WriteLine( "Error occurred during CEL initialization. " + ex.Message );
         }
      }
      ~TestCQGCEL()
      {
         // Shutdown the CQGCEL instance.
         cel.Shutdown() ;
      }
      #region CQGCEL event handlers
      private void cel_InstrumentChanged(CQGInstrument Instrument, CQGQuotes Quotes, CQGInstrumentProperties props)
      {
         // You'll get here if "DD" Instrument data is changed.
         cel.Logger.Log( "Instrument Data Changed : " + Instrument.FullName, eLogSeverity.lsInfo ) ;
      }
      private void cel_InstrumentSubscribed(string Symbl, CQGInstrument Instrument)
      {
         // You'll get here if "DD" Instrument is subscribed.
         cel.Logger.Log( "Instrument Data Changed : " + Symbl, eLogSeverity.lsInfo ) ;
      }
      private void cel_IncorrectSymbol(string Symbl)
      {
         // You'll get here if "DD" Instrument is subscribed.
         cel.Logger.Log( "INCORRECT SYMBOL: " + Symbl, eLogSeverity.lsError ) ;
      }
      private void cel_CELStarted()
      {
         // Create new instrument after CEL is started up
         cel.NewInstrument( "DD" ) ;
      }
      private void cel_IsReady(out eReadyStatus ReadyStatus)
      {
         // We are always ready to handle CQGCEL events.
         ReadyStatus = eReadyStatus.rsReady ;
      }
      private void cel_DataError(object Obj, string ErrorDescription)
      {
         cel.Logger.Log( "ERROR : " + ErrorDescription , eLogSeverity.lsError ) ;
         System.Windows.Forms.Application.Exit() ;
      }
      #endregion
      [STAThread]
      static void Main(string[] args)
      {
         TestCQGCEL test = new TestCQGCEL();
         // Start Application. Will work until some error occurred.
         System.Windows.Forms.Application.Run() ;
      }
   }
}