[DefaultValue(UsedAppointmentType.All)]
public UsedAppointmentType AllowAppointmentCopy { get; set; }

<DefaultValue(UsedAppointmentType.All)>
Public Property AllowAppointmentCopy As UsedAppointmentType

using DevExpress.XtraScheduler;
// ...

private void schedulerControl1_AllowAppointmentDelete(object sender, 
    AppointmentOperationEventArgs e) {
   // Allow only the user who created this appontment to delete it.
   e.Allow = CanUserModifyThisAppointment(e.Appointment);
}
private void schedulerControl1_AllowAppointmentEdit(object sender, 
    AppointmentOperationEventArgs e) {
   // Allow only the user who created this appontment to modify it.
   e.Allow = CanUserModifyThisAppointment(e.Appointment);
}
// Determine if the current user is the same 
// as the one who created the specified appointment 
bool CanUserModifyThisAppointment(Appointment apt) {
   object obj = apt.CustomFields["Owner"];
   if (obj == null)
      return true;
   string appointmentOwner = obj.ToString();
   if (appointmentOwner == String.Empty)
      return true;
   return (String.Compare(appointmentOwner, tbUserName.Text, true) == 0);
}

Imports DevExpress.XtraScheduler
' ...

Private Sub schedulerControl1_AllowAppointmentDelete(ByVal sender As Object, _
ByVal e As AppointmentOperationEventArgs)
   ' Allow only the user who created this appontment to delete it.
   e.Allow = CanUserModifyThisAppointment(e.Appointment)
End Sub
Private Sub schedulerControl1_AllowAppointmentEdit(ByVal sender As Object, _
ByVal e As AppointmentOperationEventArgs)
   ' Allow only the user who created this appontment to modify it.
   e.Allow = CanUserModifyThisAppointment(e.Appointment)
End Sub
' Determine if the current user is the same 
' as the one who created the specified appointment 
Private Function CanUserModifyThisAppointment(ByVal apt As Appointment) As Boolean
   Dim obj As Object = apt.CustomFields("Owner")
   If obj Is Nothing Then
      Return True
   End If
   Dim appointmentOwner As String = obj.ToString()
   If appointmentOwner = String.Empty Then
      Return True
   End If
   Return (String.Compare(appointmentOwner, tbUserName.Text, True) = 0)
End Function