/// <summary>
/// Fetches the next batch of references.
/// </summary>
/// <param name="continuationPoint">The continuation point.</param>
/// <param name="cancel">if set to <c>true</c> the browse operation is cancelled.</param>
/// <returns>The next batch of references</returns>
private ReferenceDescriptionCollection BrowseNext(ref byte[] continuationPoint, bool cancel)
{
ByteStringCollection continuationPoints = new ByteStringCollection();
continuationPoints.Add(continuationPoint);
// make the call to the server.
BrowseResultCollection results;
DiagnosticInfoCollection diagnosticInfos;
ResponseHeader responseHeader = m_session.BrowseNext(
null,
cancel,
continuationPoints,
out results,
out diagnosticInfos);
// ensure that the server returned valid results.
Session.ValidateResponse(results, continuationPoints);
Session.ValidateDiagnosticInfos(diagnosticInfos, continuationPoints);
// check if valid.
if (StatusCode.IsBad(results[0].StatusCode))
{
throw ServiceResultException.Create(results[0].StatusCode, 0, diagnosticInfos, responseHeader.StringTable);
}
// update continuation point.
continuationPoint = results[0].ContinuationPoint;
// return references.
return(results[0].References);
}
/// <summary>
/// Browses the specified node.
/// </summary>
public ReferenceDescriptionCollection Browse(NodeId nodeId)
{
if (m_session == null)
{
throw new ServiceResultException(StatusCodes.BadServerNotConnected, "Cannot browse if not connected to a server.");
}
try
{
m_browseInProgress = true;
// construct request.
BrowseDescription nodeToBrowse = new BrowseDescription();
nodeToBrowse.NodeId = nodeId;
nodeToBrowse.BrowseDirection = m_browseDirection;
nodeToBrowse.ReferenceTypeId = m_referenceTypeId;
nodeToBrowse.IncludeSubtypes = m_includeSubtypes;
nodeToBrowse.NodeClassMask = m_nodeClassMask;
nodeToBrowse.ResultMask = m_resultMask;
BrowseDescriptionCollection nodesToBrowse = new BrowseDescriptionCollection();
nodesToBrowse.Add(nodeToBrowse);
// make the call to the server.
BrowseResultCollection results;
DiagnosticInfoCollection diagnosticInfos;
ResponseHeader responseHeader = m_session.Browse(
null,
m_view,
m_maxReferencesReturned,
nodesToBrowse,
out results,
out diagnosticInfos);
// ensure that the server returned valid results.
Session.ValidateResponse(results, nodesToBrowse);
Session.ValidateDiagnosticInfos(diagnosticInfos, nodesToBrowse);
// check if valid.
if (StatusCode.IsBad(results[0].StatusCode))
{
throw ServiceResultException.Create(results[0].StatusCode, 0, diagnosticInfos, responseHeader.StringTable);
}
// fetch initial set of references.
byte[] continuationPoint = results[0].ContinuationPoint;
ReferenceDescriptionCollection references = results[0].References;
// process any continuation point.
while (continuationPoint != null)
{
ReferenceDescriptionCollection additionalReferences;
if (!m_continueUntilDone && m_MoreReferences != null)
{
BrowserEventArgs args = new BrowserEventArgs(references);
m_MoreReferences(this, args);
// cancel browser and return the references fetched so far.
if (args.Cancel)
{
BrowseNext(ref continuationPoint, true);
return(references);
}
m_continueUntilDone = args.ContinueUntilDone;
}
additionalReferences = BrowseNext(ref continuationPoint, false);
if (additionalReferences != null && additionalReferences.Count > 0)
{
references.AddRange(additionalReferences);
}
else
{
Utils.LogWarning("Browser: Continuation point exists, but the browse results are null/empty.");
break;
}
}
// return the results.
return(references);
}
finally
{
m_browseInProgress = false;
}
}