It seems to me that you are simply creating a new appointment and passing it into the Dialog. That seems to indicate that you want the new appointment to be created whether the user Cancels the dialog or not. If that's the case, then it makes this very easy.

Right now, you are creating the new appointment, but you are just creating it outside of the CalendarInfo. So maybe all you need to do is add it to the Appointments collection and THEN show the dialog. Since the appointment is an existing appointment in this case, and not a new one, the DataKey and other properties ARE maintained. 

So something like this:

        Dim MyAppt As Appointment
        MyAppt = New Appointment(DateTime.Now, DateTime.Now.AddHours(1))
        MyAppt.DataKey = DateTime.Now.Ticks
        Me.UltraCalendarInfo1.Appointments.Add(MyAppt)
        Me.UltraCalendarInfo1.DisplayAppointmentDialog(MyAppt)

Actually... when I do it this way, creating the Appointment and passing it in to Me.UltraCalendarInfo1.DisplayAppointmentDialog, the DataKey seems to be maintained, even if I DON'T add the appointment to the Appointments collection. So even if you comment out the second-to-last line of code above, it still works. I guess since I am passing an existing appointment object into the dialog, even though that Appointment is not in the CalendarInfo.Appointments collection, it treats it as an existing appointment and doesn't lose the extra data that is not in the UI. 

So I think that should solve the issue for you either way.

Okay... I think I see the issue. 

So if the appointment doesn't already exist, you need to create a new one and show the dialog and you have the ID you need before showing the dialog, since you got it from the grid. 

So really all you need to do is store that information - and then apply it to the appointment that got created by the dialog. But you also need to know if the user cancelled the dialog and did NOT create the appointment. 

Or... do you want the appointment to get created even if the use cancels the dialog? 

Ok, I will give you the 10,000 foot view, then ask a question at the end. I have an old stable application that would benefit from a scheduling function. I need to tie my existing database into the appointments, so I will use the tag field. There is an existing search / filter function in my app for the users case assignments. Those cases are displayed in an UltraWinGrid. Using the Tag, I retrieve the appointment date (if any) and display it in the grid. If they click on that I want to be able to edit that appointment. If there is no existing appointment, then I display the appointment dialog (using AppointmentDialog2007 VB.frmAppointmentDialog2007 as a template). I have the "add new" part working. I just need to know how to retrieve an existing appointment object using either the Tag or AppointmentID so I can pass it to the dialog. The ???? below is what I need. The code looks like this:

If mblnNew Then 'mblnNew indicates if this is an existing appointment
Dim MyAppt As New Infragistics.Win.UltraWinSchedule.Appointment(dtSchedDate, dtSchedDate.AddHours(2))
Dim e As New Infragistics.Win.UltraWinSchedule.DisplayAppointmentDialogEventArgs(MyAppt, False)
e.Appointment.Subject = "Case ID: " & CaseID.ToString & " Customer Name: " & mstrPassCaseName
e.Appointment.Description = "Case ID: " & CaseID.ToString & " Customer Name: " & mstrPassCaseName
e.Appointment.StartDateTime = dtSchedDate
e.Appointment.EndDateTime = dtSchedDate.AddHours(2)
e.Appointment.CalendarInfo = ultraCalendarInfo1
e.Appointment.Tag = mlngAuditID.ToString
e.Appointment.OwnerKey = gstrSecuID
Else
'TODO: Get existing data here and populate appointment
Dim MyAppt As ???? <existing appointment retrieved by AppointmentID or Tag>
Dim e As New Infragistics.Win.UltraWinSchedule.DisplayAppointmentDialogEventArgs(MyAppt, False)
End If

ApptDlg = New AppointmentDialog2007
ApptDlg.Show(e.Appointment, Me.ultraCalendarInfo1, Me.ultraCalendarLook1, <some other stuff I pass>, mblnNew)

I'm not sure I understand what you mean by multiple appointments at once. The dialog only creates a single appointment. And the user can only create one at a time. 

Also... DataBinding has nothing to do with this, really. I did all my testing completely unbound. The dialog is the issue here. 

And yes, it will throw away anything that is not visible in the dialog's UI when you create a NEW Appointment. 

It's not really clear to me what you are trying to achieve here, or why you would know what the DataKey (or Tag) is before the appointment is created, but not after. 

My current thinking is to just do all the data I/O manually, rather than use binding on the appointment itself. Not sure that's possible yet - keeping the monthly / weekly views bound to the data, then calling my own appointment dialog like the "AppointmentDialog2007 VB" demo. I would have to capture the appropriate events and do my own insert / update / deletes. Then rebind the source control (ultraMonthViewSingle for example) if necessary (will cross that bridge if I ever come to it).