/// <summary>
/// Continues a browse operation with previously specified search criteria.
/// </summary>
/// <param name="position">An object containing the browse operation state information.</param>
/// <returns>The set of elements found.</returns>
public virtual TsCDaBrowseElement[] BrowseNext(ref Technosoftware.DaAeHdaClient.Da.TsCDaBrowsePosition position)
{
lock (this)
{
if (m_server == null)
{
throw new NotConnectedException();
}
string methodName = "IOPCBrowse.Browse";
// check for valid position object.
if (position == null || position.GetType() != typeof(Technosoftware.DaAeHdaClient.Com.Da.BrowsePosition))
{
throw new BrowseCannotContinueException();
}
Technosoftware.DaAeHdaClient.Com.Da.BrowsePosition pos = (Technosoftware.DaAeHdaClient.Com.Da.BrowsePosition)position;
// check for valid continuation point.
if (pos == null || pos.ContinuationPoint == null || pos.ContinuationPoint == "")
{
throw new BrowseCannotContinueException();
}
// initialize arguments.
int count = 0;
int moreElements = 0;
OpcItem itemID = ((BrowsePosition)position).ItemID;
TsCDaBrowseFilters filters = ((BrowsePosition)position).Filters;
IntPtr pContinuationPoint = Marshal.StringToCoTaskMemUni(pos.ContinuationPoint);
IntPtr pElements = IntPtr.Zero;
// invoke COM method.
try
{
IOPCBrowse server = BeginComCall <IOPCBrowse>(methodName, true);
server.Browse(
(itemID != null && itemID.ItemName != null) ? itemID.ItemName : "",
ref pContinuationPoint,
filters.MaxElementsReturned,
Technosoftware.DaAeHdaClient.Com.Da.Interop.GetBrowseFilter(filters.BrowseFilter),
(filters.ElementNameFilter != null) ? filters.ElementNameFilter : "",
(filters.VendorFilter != null) ? filters.VendorFilter : "",
(filters.ReturnAllProperties) ? 1 : 0,
(filters.ReturnPropertyValues) ? 1 : 0,
(filters.PropertyIDs != null) ? filters.PropertyIDs.Length : 0,
Technosoftware.DaAeHdaClient.Com.Da.Interop.GetPropertyIDs(filters.PropertyIDs),
out moreElements,
out count,
out pElements);
}
catch (Exception e)
{
ComCallError(methodName, e);
throw Technosoftware.DaAeHdaClient.Com.Interop.CreateException(methodName, e);
}
finally
{
EndComCall(methodName);
}
// unmarshal results.
TsCDaBrowseElement[] elements = Technosoftware.DaAeHdaClient.Com.Da.Interop.GetBrowseElements(ref pElements, count, true);
pos.ContinuationPoint = Marshal.PtrToStringUni(pContinuationPoint);
Marshal.FreeCoTaskMem(pContinuationPoint);
// check if more no results exist.
if (moreElements == 0 && (pos.ContinuationPoint == null || pos.ContinuationPoint == ""))
{
position = null;
}
// process results.
ProcessResults(elements, filters.PropertyIDs);
return(elements);
}
}
/// <summary>
/// Fetches the children of a branch that meet the filter criteria.
/// </summary>
/// <param name="itemID">The identifier of branch which is the target of the search.</param>
/// <param name="filters">The filters to use to limit the set of child elements returned.</param>
/// <param name="position">An object used to continue a browse that could not be completed.</param>
/// <returns>The set of elements found.</returns>
public virtual TsCDaBrowseElement[] Browse(
OpcItem itemID,
TsCDaBrowseFilters filters,
out Technosoftware.DaAeHdaClient.Da.TsCDaBrowsePosition position)
{
if (filters == null)
{
throw new ArgumentNullException(nameof(filters));
}
lock (this)
{
if (m_server == null)
{
throw new NotConnectedException();
}
string methodName = "IOPCBrowse.Browse";
position = null;
// initialize arguments.
int count = 0;
int moreElements = 0;
IntPtr pContinuationPoint = IntPtr.Zero;
IntPtr pElements = IntPtr.Zero;
// invoke COM method.
try
{
IOPCBrowse server = BeginComCall <IOPCBrowse>(methodName, true);
server.Browse(
(itemID != null && itemID.ItemName != null) ? itemID.ItemName : "",
ref pContinuationPoint,
filters.MaxElementsReturned,
Technosoftware.DaAeHdaClient.Com.Da.Interop.GetBrowseFilter(filters.BrowseFilter),
(filters.ElementNameFilter != null) ? filters.ElementNameFilter : "",
(filters.VendorFilter != null) ? filters.VendorFilter : "",
(filters.ReturnAllProperties) ? 1 : 0,
(filters.ReturnPropertyValues) ? 1 : 0,
(filters.PropertyIDs != null) ? filters.PropertyIDs.Length : 0,
Technosoftware.DaAeHdaClient.Com.Da.Interop.GetPropertyIDs(filters.PropertyIDs),
out moreElements,
out count,
out pElements);
}
catch (Exception e)
{
ComCallError(methodName, e);
throw Technosoftware.DaAeHdaClient.Com.Interop.CreateException(methodName, e);
}
finally
{
EndComCall(methodName);
}
// unmarshal results.
TsCDaBrowseElement[] elements = Technosoftware.DaAeHdaClient.Com.Da.Interop.GetBrowseElements(ref pElements, count, true);
string continuationPoint = Marshal.PtrToStringUni(pContinuationPoint);
Marshal.FreeCoTaskMem(pContinuationPoint);
// check if more results exist.
if (moreElements != 0 || (continuationPoint != null && continuationPoint != ""))
{
// allocate new browse position object.
position = new Technosoftware.DaAeHdaClient.Com.Da.BrowsePosition(itemID, filters, continuationPoint);
}
// process results.
ProcessResults(elements, filters.PropertyIDs);
return(elements);
}
}