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)));
}
}
