/// <summary>
/// Creates an enumerator for the current browse position.
/// </summary>
/// <param name="sources">if set to <c>true</c> then sources are enumerated.</param>
/// <returns>The wrapped enumerator.</returns>
private EnumString CreateEnumerator(bool sources)
{
IEnumString unknown = null;
string methodName = "IOPCEventAreaBrowser.BrowseOPCAreas";
try
{
IOPCEventAreaBrowser server = BeginComCall <IOPCEventAreaBrowser>(methodName, true);
OPCAEBROWSETYPE browseType = OPCAEBROWSETYPE.OPC_AREA;
if (sources)
{
browseType = OPCAEBROWSETYPE.OPC_SOURCE;
}
server.BrowseOPCAreas(browseType, String.Empty, out unknown);
}
catch (Exception e)
{
ComCallError(methodName, e);
return(null);
}
finally
{
EndComCall(methodName);
}
// wrapper the enumrator. hardcoding a buffer size of 256.
return(new EnumString(unknown, 256));
}
private bool IsValidNode(NodeId nodeId, string nodeName, OPCAEBROWSETYPE dwBrowseFilterType)
{
Browser browse = new Browser(m_session);
ReferenceDescriptionCollection references = null;
try
{
// For a node to be an area, it has to have the 'HasNotifier' reference and must
// allow event notification (the EventNotifier attribute is set to SubscribeToEvents)
if (dwBrowseFilterType == OPCAEBROWSETYPE.OPC_AREA)
{
// if node is 'Server' then the HasNotifier is implicit, so return true
if (nodeName == "Server")
{
return(true);
}
references = browse.Browse(nodeId);
foreach (ReferenceDescription reference in references)
{
if ((reference.ReferenceTypeId == ReferenceTypes.HasNotifier) || (reference.ReferenceTypeId == ReferenceTypes.HasEventSource))
{
return(IsEventNotificationListAllowed(nodeId));
}
}
}
// For a node to be a source, it should be the target of the HasEventSource reference
else // Check if this is a source.
{
IList <INode> parent = m_session.NodeCache.Find(nodeId, ReferenceTypes.HasEventSource, true, false);
if (parent.Count != 0)
{
return(true);
}
}
}
catch (Exception e)
{
Utils.Trace(e, "Unexpected error in IsValidNode");
}
return(false);
}
private object CreateEnumerator(BrowseType browseType, string browseFilter)
{
OPCAEBROWSETYPE dwBrowseFilterType = OpcCom.Ae.Interop.GetBrowseType(browseType);
IEnumString ppIEnumString = null;
try
{
((IOPCEventAreaBrowser) this.m_browser).BrowseOPCAreas(dwBrowseFilterType, (browseFilter != null) ? browseFilter : "", out ppIEnumString);
}
catch (Exception exception)
{
throw OpcCom.Interop.CreateException("IOPCEventAreaBrowser.BrowseOPCAreas", exception);
}
if (ppIEnumString == null)
{
throw new InvalidResponseException("enumerator == null");
}
return ppIEnumString;
}
private bool IsValidNode(NodeId nodeId, string nodeName, OPCAEBROWSETYPE dwBrowseFilterType)
{
Browser browse = new Browser(m_session);
ReferenceDescriptionCollection references = null;
try
{
// For a node to be an area, it has to have the 'HasNotifier' reference and must
// allow event notification (the EventNotifier attribute is set to SubscribeToEvents)
if (dwBrowseFilterType == OPCAEBROWSETYPE.OPC_AREA)
{
// if node is 'Server' then the HasNotifier is implicit, so return true
if (nodeName == "Server")
{
return true;
}
references = browse.Browse(nodeId);
foreach (ReferenceDescription reference in references)
{
if ((reference.ReferenceTypeId == ReferenceTypes.HasNotifier) || (reference.ReferenceTypeId == ReferenceTypes.HasEventSource))
{
return IsEventNotificationListAllowed(nodeId);
}
}
}
// For a node to be a source, it should be the target of the HasEventSource reference
else // Check if this is a source.
{
IList<INode> parent = m_session.NodeCache.Find(nodeId, ReferenceTypes.HasEventSource, true, false);
if (parent.Count != 0)
return true;
}
}
catch (Exception e)
{
Utils.Trace(e, "Unexpected error in IsValidNode");
}
return false;
}
/// <summary>
/// Return an IEnumString for a list of Areas as determined by the passed parameters.
/// </summary>
/// <param name="dwBrowseFilterType">
/// OPC_AREA - returns only areas.
/// OPC_SOURCE - returns only sources.</param>
/// <param name="szFilterCriteria">A server specific filter string. A pointer to a NULL string indicates no filtering.</param>
/// <param name="ppIEnumString">Where to save the returned interface pointer. NULL if the HRESULT is other than S_OK or S_FALSE.</param>
public void BrowseOPCAreas(
OPCAEBROWSETYPE dwBrowseFilterType,
string szFilterCriteria,
out OpcRcw.Comn.IEnumString ppIEnumString)
{
ppIEnumString = null;
if (dwBrowseFilterType != OPCAEBROWSETYPE.OPC_AREA && dwBrowseFilterType != OPCAEBROWSETYPE.OPC_SOURCE)
{
throw ComUtils.CreateComException("BrowseOPCAreas", ResultIds.E_INVALIDARG);
}
try
{
lock (m_lock)
{
// find the current node.
INode parent = null;
// ensure browse stack has been initialized.
if (m_browseStack.Count == 0)
{
parent = m_session.NodeCache.Find(Objects.Server);
m_browseStack.Push(parent);
}
parent = m_browseStack.Peek();
if (parent == null)
{
throw ComUtils.CreateComException("BrowseOPCAreas",ResultIds.E_FAIL);
}
List<string> names = new List<string>();
IList<INode> children;
////// find children.
children = m_session.NodeCache.Find(parent.NodeId, ReferenceTypes.HasEventSource, false, true); // This would also include
// the HasNotifier reference which is
// a subtype of HasEventSource
foreach (INode child in children)
{
// ignore external nodes.
if (child.NodeId.IsAbsolute)
{
continue;
}
// ignore non-objects/variables.
if ((child.NodeClass & (NodeClass.Object | NodeClass.Variable)) == 0)
{
continue;
}
// ignore duplicate browse names.
if (names.Contains(child.BrowseName.ToString()))
{
continue;
}
// For a node to be an area, it has to have the 'HasNotifier' reference and must
// allow event notification (the EventNotifier attribute is set to SubscribeToEvents)
// For a node to be a source, it should be the target of the HasEventSource reference
if (IsValidNode((NodeId)child.NodeId, child.BrowseName.ToString(), dwBrowseFilterType))
{
if (String.IsNullOrEmpty(szFilterCriteria))
{
names.Add(child.BrowseName.ToString());
}
else
{
// apply filters
if (ComUtils.Match(child.BrowseName.ToString(), szFilterCriteria, true))
{
names.Add(child.BrowseName.ToString());
}
}
}
}
// create enumerator.
ppIEnumString = (OpcRcw.Comn.IEnumString)new EnumString(names);
}
}
catch (Exception e)
{
Utils.Trace(e, "Unexpected error in BrowseOPCAreas");
throw ComUtils.CreateComException(e);
}
}
/// <summary>
/// Return an IEnumString for a list of Areas as determined by the passed parameters.
/// </summary>
/// <param name="dwBrowseFilterType">
/// OPC_AREA - returns only areas.
/// OPC_SOURCE - returns only sources.</param>
/// <param name="szFilterCriteria">A server specific filter string. A pointer to a NULL string indicates no filtering.</param>
/// <param name="ppIEnumString">Where to save the returned interface pointer. NULL if the HRESULT is other than S_OK or S_FALSE.</param>
public void BrowseOPCAreas(
OPCAEBROWSETYPE dwBrowseFilterType,
string szFilterCriteria,
out OpcRcw.Comn.IEnumString ppIEnumString)
{
ppIEnumString = null;
if (dwBrowseFilterType != OPCAEBROWSETYPE.OPC_AREA && dwBrowseFilterType != OPCAEBROWSETYPE.OPC_SOURCE)
{
throw ComUtils.CreateComException("BrowseOPCAreas", ResultIds.E_INVALIDARG);
}
try
{
lock (m_lock)
{
// find the current node.
INode parent = null;
// ensure browse stack has been initialized.
if (m_browseStack.Count == 0)
{
parent = m_session.NodeCache.Find(Objects.Server);
m_browseStack.Push(parent);
}
parent = m_browseStack.Peek();
if (parent == null)
{
throw ComUtils.CreateComException("BrowseOPCAreas", ResultIds.E_FAIL);
}
List <string> names = new List <string>();
IList <INode> children;
////// find children.
children = m_session.NodeCache.Find(parent.NodeId, ReferenceTypes.HasEventSource, false, true); // This would also include
// the HasNotifier reference which is
// a subtype of HasEventSource
foreach (INode child in children)
{
// ignore external nodes.
if (child.NodeId.IsAbsolute)
{
continue;
}
// ignore non-objects/variables.
if ((child.NodeClass & (NodeClass.Object | NodeClass.Variable)) == 0)
{
continue;
}
// ignore duplicate browse names.
if (names.Contains(child.BrowseName.ToString()))
{
continue;
}
// For a node to be an area, it has to have the 'HasNotifier' reference and must
// allow event notification (the EventNotifier attribute is set to SubscribeToEvents)
// For a node to be a source, it should be the target of the HasEventSource reference
if (IsValidNode((NodeId)child.NodeId, child.BrowseName.ToString(), dwBrowseFilterType))
{
if (String.IsNullOrEmpty(szFilterCriteria))
{
names.Add(child.BrowseName.ToString());
}
else
{
// apply filters
if (ComUtils.Match(child.BrowseName.ToString(), szFilterCriteria, true))
{
names.Add(child.BrowseName.ToString());
}
}
}
}
// create enumerator.
ppIEnumString = (OpcRcw.Comn.IEnumString) new EnumString(names);
}
}
catch (Exception e)
{
Utils.Trace(e, "Unexpected error in BrowseOPCAreas");
throw ComUtils.CreateComException(e);
}
}
