SqlNotificationType.Change is always subscribe not changing even after insert or update or delete occure

If e.Type = SqlNotificationType.Change Then
        Dim nHub As New NotificationHub()
        nHub.SendNotifications()
    End If

 If e.Info = SqlNotificationInfo.Insert _
    Or e.Info = SqlNotificationInfo.Delete _
    Or e.Info = SqlNotificationInfo.Update Then
             Dim nHub As New NotificationHub()
             nHub.SendNotifications()   
    End If