public BrowseElement[] BrowseNext(int maxElements, ref IBrowsePosition position) { if (position == null || (object)position.GetType() != typeof(BrowsePosition)) { throw new ArgumentException("Not a valid browse position object.", "position"); } if (maxElements <= 0) { maxElements = int.MaxValue; } lock (this) { BrowsePosition browsePosition = (BrowsePosition)position; ArrayList arrayList = new ArrayList(); if (!browsePosition.FetchingItems) { arrayList = FetchElements(browsePosition.Enumerator, maxElements, isBranch: true); if (arrayList.Count >= maxElements) { return((BrowseElement[])arrayList.ToArray(typeof(BrowseElement))); } browsePosition.Enumerator.Dispose(); browsePosition.Enumerator = null; browsePosition.FetchingItems = true; try { m_browser.ChangeBrowsePosition(OPCHDA_BROWSEDIRECTION.OPCHDA_BROWSE_DIRECT, browsePosition.BranchPath); } catch (Exception e) { throw OpcCom.Interop.CreateException("IOPCHDA_Browser.ChangeBrowsePosition", e); } browsePosition.Enumerator = GetEnumerator(isBranch: false); } ArrayList arrayList2 = FetchElements(browsePosition.Enumerator, maxElements - arrayList.Count, isBranch: false); if (arrayList2 != null) { arrayList.AddRange(arrayList2); } if (arrayList.Count >= maxElements) { return((BrowseElement[])arrayList.ToArray(typeof(BrowseElement))); } position.Dispose(); position = null; return((BrowseElement[])arrayList.ToArray(typeof(BrowseElement))); } }
public BrowseElement[] Browse(ItemIdentifier itemID, int maxElements, out IBrowsePosition position) { position = null; if (maxElements <= 0) { maxElements = int.MaxValue; } lock (this) { string text = (itemID != null && itemID.ItemName != null) ? itemID.ItemName : ""; try { m_browser.ChangeBrowsePosition(OPCHDA_BROWSEDIRECTION.OPCHDA_BROWSE_DIRECT, text); } catch (Exception e) { throw OpcCom.Interop.CreateException("IOPCHDA_Browser.ChangeBrowsePosition", e); } EnumString enumerator = GetEnumerator(isBranch: true); ArrayList arrayList = FetchElements(enumerator, maxElements, isBranch: true); if (arrayList.Count >= maxElements) { position = new BrowsePosition(text, enumerator, fetchingItems: false); return((BrowseElement[])arrayList.ToArray(typeof(BrowseElement))); } enumerator.Dispose(); enumerator = GetEnumerator(isBranch: false); ArrayList arrayList2 = FetchElements(enumerator, maxElements - arrayList.Count, isBranch: false); if (arrayList2 != null) { arrayList.AddRange(arrayList2); } if (arrayList.Count >= maxElements) { position = new BrowsePosition(text, enumerator, fetchingItems: true); return((BrowseElement[])arrayList.ToArray(typeof(BrowseElement))); } enumerator.Dispose(); return((BrowseElement[])arrayList.ToArray(typeof(BrowseElement))); } }
/// <summary> /// Begins a browsing the server's address space at the specified branch. /// </summary> /// <param name="itemID">The item id of the branch to search.</param> /// <param name="maxElements">The maximum number of elements to return.</param> /// <param name="position">The position object used to continue a browse operation.</param> /// <returns>The set of elements that meet the filter criteria.</returns> public BrowseElement[] Browse(ItemIdentifier itemID, int maxElements, out IBrowsePosition position) { position = null; // interpret invalid values as 'no limit'. if (maxElements <= 0) { maxElements = Int32.MaxValue; } lock (this) { string branchPath = (itemID != null && itemID.ItemName != null)?itemID.ItemName:""; // move to the correct position in the server's address space. try { m_browser.ChangeBrowsePosition(OPCHDA_BROWSEDIRECTION.OPCHDA_BROWSE_DIRECT, branchPath); } catch (Exception e) { throw OpcCom.Interop.CreateException("IOPCHDA_Browser.ChangeBrowsePosition", e); } // browse for branches EnumString enumerator = GetEnumerator(true); ArrayList elements = FetchElements(enumerator, maxElements, true); // check if max element count reached. if (elements.Count >= maxElements) { position = new BrowsePosition(branchPath, enumerator, false); return((BrowseElement[])elements.ToArray(typeof(BrowseElement))); } // release enumerator. enumerator.Dispose(); // browse for items enumerator = GetEnumerator(false); ArrayList items = FetchElements(enumerator, maxElements - elements.Count, false); if (items != null) { elements.AddRange(items); } // check if max element count reached. if (elements.Count >= maxElements) { position = new BrowsePosition(branchPath, enumerator, true); return((BrowseElement[])elements.ToArray(typeof(BrowseElement))); } // release enumerator. enumerator.Dispose(); return((BrowseElement[])elements.ToArray(typeof(BrowseElement))); } }