/// <summary>
/// Raised when a publish response arrives from the server.
/// </summary>
/// <param name="session">The target of the event.</param>
/// <param name="e">The <see cref="Opc.Ua.Client.NotifacationEventArgs"/>Instance containing the event data.</param>
private void Session_Notification(Session session, NotificationEventArgs e)
{
NotificationMessage message = e.NotificationMessage;
// Check for keep alive.
if (message.NotificationData.Count == 0)
{
return;
}
// Get the data changes (oldest to newest).
foreach (MonitoredItemNotification datachange in message.GetDataChanges(false))
{
// Lookup the monitored item.
MonitoredItem monitoredItem = e.Subscription.FindItemByClientHandle(datachange.ClientHandle);
if (monitoredItem == null)
{
continue;
}
ClientMonitoredItemData clientData = monitoredItem.Handle as ClientMonitoredItemData;
clientData.callback(clientData.clientHandle, datachange.Value);
}
}
/// <summary>
/// Creates a monitored item and adds it to the existing subscription.
/// </summary>
/// <param name="variableNodeId">The according nodeid.</param>
/// <param name="clientHandle">The handle of the client registering items.</param>
/// <param name="callback">The callback to retrieve value changes.</param>
/// <param name="samplingRate">The requested sampling rate.</param>
/// <param name="serverHandle">The handle of the item.</param>
public void AddDataMonitoredItem(NodeId variableNodeId, object clientHandle, valueChanged callback, uint samplingRate, out object serverHandle)
{
serverHandle = null;
try
{
MonitoredItem monitoredItem = new MonitoredItem(m_Subscription.DefaultItem);
ClientMonitoredItemData clientData = new ClientMonitoredItemData();
clientData.callback = callback;
clientData.clientHandle = clientHandle;
// Monitored item settings:
monitoredItem.StartNodeId = variableNodeId;
monitoredItem.AttributeId = Attributes.Value;
monitoredItem.MonitoringMode = MonitoringMode.Reporting;
monitoredItem.SamplingInterval = (int)samplingRate; // Affects the read cycle between UA Server and data source
monitoredItem.QueueSize = 1;
monitoredItem.DiscardOldest = false;
monitoredItem.Handle = clientData;
// Add item to subscription.
m_Subscription.AddItem(monitoredItem);
// Call the server and apply any changes to the state of the subscription or monitored items.
m_Subscription.ApplyChanges();
// Check result of add.
if (monitoredItem.Status.Error != null && StatusCode.IsBad(monitoredItem.Status.Error.StatusCode))
{
throw ServiceResultException.Create(
monitoredItem.Status.Error.StatusCode.Code,
"Creation of data monitored item failed");
}
serverHandle = monitoredItem;
myMonitorItemServerHandlerList.Add(serverHandle);
}
catch (Exception e)
{
throw e;
}
}