/// <summary>
/// Collects the fields for the instance node.
/// </summary>
/// <param name="session">The session.</param>
/// <param name="nodeId">The node id.</param>
/// <param name="parentPath">The parent path.</param>
/// <param name="fields">The event fields.</param>
/// <param name="fieldNodeIds">The node id for the declaration of the field.</param>
/// <param name="foundNodes">The table of found nodes.</param>
private static void CollectFields(
Session session,
NodeId nodeId,
QualifiedNameCollection parentPath,
SimpleAttributeOperandCollection fields,
List <NodeId> fieldNodeIds,
Dictionary <NodeId, QualifiedNameCollection> foundNodes)
{
// find all of the children of the field.
BrowseDescription nodeToBrowse = new BrowseDescription();
nodeToBrowse.NodeId = nodeId;
nodeToBrowse.BrowseDirection = BrowseDirection.Forward;
nodeToBrowse.ReferenceTypeId = ReferenceTypeIds.Aggregates;
nodeToBrowse.IncludeSubtypes = true;
nodeToBrowse.NodeClassMask = (uint)(NodeClass.Object | NodeClass.Variable);
nodeToBrowse.ResultMask = (uint)BrowseResultMask.All;
ReferenceDescriptionCollection children = FormUtils.Browse(session, nodeToBrowse, false);
if (children == null)
{
return;
}
// process the children.
for (int ii = 0; ii < children.Count; ii++)
{
ReferenceDescription child = children[ii];
if (child.NodeId.IsAbsolute)
{
continue;
}
// construct browse path.
QualifiedNameCollection browsePath = new QualifiedNameCollection(parentPath);
browsePath.Add(child.BrowseName);
// check if the browse path is already in the list.
int index = ContainsPath(fields, browsePath);
if (index < 0)
{
SimpleAttributeOperand field = new SimpleAttributeOperand();
field.TypeDefinitionId = ObjectTypeIds.BaseEventType;
field.BrowsePath = browsePath;
field.AttributeId = (child.NodeClass == NodeClass.Variable) ? Attributes.Value : Attributes.NodeId;
fields.Add(field);
fieldNodeIds.Add((NodeId)child.NodeId);
}
// recusively find all of the children.
NodeId targetId = (NodeId)child.NodeId;
// need to guard against loops.
if (!foundNodes.ContainsKey(targetId))
{
foundNodes.Add(targetId, browsePath);
CollectFields(session, (NodeId)child.NodeId, browsePath, fields, fieldNodeIds, foundNodes);
}
}
}
/// <summary>
/// Constructs an event object from a notification.
/// </summary>
/// <param name="session">The session.</param>
/// <param name="monitoredItem">The monitored item that produced the notification.</param>
/// <param name="notification">The notification.</param>
/// <param name="knownEventTypes">The known event types.</param>
/// <param name="eventTypeMappings">Mapping between event types and known event types.</param>
/// <returns>
/// The event object. Null if the notification is not a valid event type.
/// </returns>
public static BaseEventState ConstructEvent(
Session session,
MonitoredItem monitoredItem,
EventFieldList notification,
Dictionary <NodeId, Type> knownEventTypes,
Dictionary <NodeId, NodeId> eventTypeMappings)
{
// find the event type.
NodeId eventTypeId = FindEventType(monitoredItem, notification);
if (eventTypeId == null)
{
return(null);
}
// look up the known event type.
Type knownType = null;
NodeId knownTypeId = null;
if (eventTypeMappings.TryGetValue(eventTypeId, out knownTypeId))
{
knownType = knownEventTypes[knownTypeId];
}
// try again.
if (knownType == null)
{
if (knownEventTypes.TryGetValue(eventTypeId, out knownType))
{
knownTypeId = eventTypeId;
eventTypeMappings.Add(eventTypeId, eventTypeId);
}
}
// try mapping it to a known type.
if (knownType == null)
{
// browse for the supertypes of the event type.
ReferenceDescriptionCollection supertypes = FormUtils.BrowseSuperTypes(session, eventTypeId, false);
// can't do anything with unknown types.
if (supertypes == null)
{
return(null);
}
// find the first supertype that matches a known event type.
for (int ii = 0; ii < supertypes.Count; ii++)
{
NodeId superTypeId = (NodeId)supertypes[ii].NodeId;
if (knownEventTypes.TryGetValue(superTypeId, out knownType))
{
knownTypeId = superTypeId;
eventTypeMappings.Add(eventTypeId, superTypeId);
}
if (knownTypeId != null)
{
break;
}
}
// can't do anything with unknown types.
if (knownTypeId == null)
{
return(null);
}
}
// construct the event based on the known event type.
BaseEventState e = (BaseEventState)Activator.CreateInstance(knownType, new object[] { (NodeState)null });
// get the filter which defines the contents of the notification.
EventFilter filter = monitoredItem.Status.Filter as EventFilter;
// initialize the event with the values in the notification.
e.Update(session.SystemContext, filter.SelectClauses, notification);
// save the orginal notification.
e.Handle = notification;
return(e);
}