Bulk sms finishing


is there a way to detect if the library is finished sending? I add my messages to the the outbox using :

oGsmModem.SendSMSToOutbox(tmpSms.PhoneNumber, Me.SMSMessage.Trim)

I can check the status using the oGsmModem.OutboxSMSSent event. But is there a way to check if the last message has been send? I have a usercontrol that shows the sending progress and then I can close the control.