/// <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); } }