private void ModifyButton_Click(object sender, RibbonControlEventArgs e) { Inspector inspector = (sender as RibbonButton).Ribbon.Context as Inspector; AppointmentItem appt = inspector.CurrentItem as AppointmentItem; var creator = appt.PropertyAccessor.GetProperty("http://schemas.microsoft.com/mapi/proptag/0x0C1A001E"); if ((appt.Organizer != inspector.Session.CurrentUser.Name) && (creator != inspector.Session.CurrentUser.Name)) { DisplayManager.ShowErrorWindow("Modifying this resvervation is not allowed.", "Only the meeting organizer can modify the reservation in MRBS."); return; } _processWrite = false; OutlookManager.ModifyReservation(appt); _processWrite = true; ConferenceRoomRibbon_Load((sender as RibbonButton).Ribbon, null); }