public BrowseElement[] BrowseNext(int maxElements, ref IBrowsePosition position)
{
if ((position == null) || (position.GetType() != typeof(OpcCom.Hda.BrowsePosition)))
{
throw new ArgumentException("Not a valid browse position object.", "position");
}
if (maxElements <= 0)
{
maxElements = 0x7fffffff;
}
lock (this)
{
OpcCom.Hda.BrowsePosition position2 = (OpcCom.Hda.BrowsePosition)position;
ArrayList list = new ArrayList();
if (!position2.FetchingItems)
{
list = this.FetchElements(position2.Enumerator, maxElements, true);
if (list.Count >= maxElements)
{
return((BrowseElement[])list.ToArray(typeof(BrowseElement)));
}
position2.Enumerator.Dispose();
position2.Enumerator = null;
position2.FetchingItems = true;
try
{
this.m_browser.ChangeBrowsePosition(OPCHDA_BROWSEDIRECTION.OPCHDA_BROWSE_DIRECT, position2.BranchPath);
}
catch (Exception exception)
{
throw OpcCom.Interop.CreateException("IOPCHDA_Browser.ChangeBrowsePosition", exception);
}
position2.Enumerator = this.GetEnumerator(false);
}
ArrayList c = this.FetchElements(position2.Enumerator, maxElements - list.Count, false);
if (c != null)
{
list.AddRange(c);
}
if (list.Count < maxElements)
{
position.Dispose();
position = null;
}
return((BrowseElement[])list.ToArray(typeof(BrowseElement)));
}
}
public BrowseElement[] Browse(ItemIdentifier itemID, int maxElements, out IBrowsePosition position)
{
position = null;
if (maxElements <= 0)
{
maxElements = 0x7fffffff;
}
lock (this)
{
string szString = ((itemID != null) && (itemID.ItemName != null)) ? itemID.ItemName : "";
try
{
this.m_browser.ChangeBrowsePosition(OPCHDA_BROWSEDIRECTION.OPCHDA_BROWSE_DIRECT, szString);
}
catch (Exception exception)
{
throw OpcCom.Interop.CreateException("IOPCHDA_Browser.ChangeBrowsePosition", exception);
}
EnumString enumerator = this.GetEnumerator(true);
ArrayList list = this.FetchElements(enumerator, maxElements, true);
if (list.Count >= maxElements)
{
position = new OpcCom.Hda.BrowsePosition(szString, enumerator, false);
return((BrowseElement[])list.ToArray(typeof(BrowseElement)));
}
enumerator.Dispose();
enumerator = this.GetEnumerator(false);
ArrayList c = this.FetchElements(enumerator, maxElements - list.Count, false);
if (c != null)
{
list.AddRange(c);
}
if (list.Count >= maxElements)
{
position = new OpcCom.Hda.BrowsePosition(szString, enumerator, true);
return((BrowseElement[])list.ToArray(typeof(BrowseElement)));
}
enumerator.Dispose();
return((BrowseElement[])list.ToArray(typeof(BrowseElement)));
}
}
//======================================================================
// BrowseNext
/// <summary>
/// Continues browsing the server's address space at the specified position.
/// </summary>
/// <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[] BrowseNext(int maxElements, ref IBrowsePosition position)
{
// check arguments.
if (position == null || position.GetType() != typeof(OpcCom.Hda.BrowsePosition))
{
throw new ArgumentException("Not a valid browse position object.", "position");
}
// interpret invalid values as 'no limit'.
if (maxElements <= 0)
{
maxElements = Int32.MaxValue;
}
lock (this)
{
OpcCom.Hda.BrowsePosition pos = (OpcCom.Hda.BrowsePosition)position;
ArrayList elements = new ArrayList();
if (!pos.FetchingItems)
{
elements = FetchElements(pos.Enumerator, maxElements, true);
// check if max element count reached.
if (elements.Count >= maxElements)
{
return((BrowseElement[])elements.ToArray(typeof(BrowseElement)));
}
// release enumerator.
pos.Enumerator.Dispose();
pos.Enumerator = null;
pos.FetchingItems = true;
// move to the correct position in the server's address space.
try
{
m_browser.ChangeBrowsePosition(OPCHDA_BROWSEDIRECTION.OPCHDA_BROWSE_DIRECT, pos.BranchPath);
}
catch (Exception e)
{
throw OpcCom.Interop.CreateException("IOPCHDA_Browser.ChangeBrowsePosition", e);
}
// create enumerator for items.
pos.Enumerator = GetEnumerator(false);
}
// fetch next set of items.
ArrayList items = FetchElements(pos.Enumerator, maxElements - elements.Count, false);
if (items != null)
{
elements.AddRange(items);
}
// check if max element count reached.
if (elements.Count >= maxElements)
{
return((BrowseElement[])elements.ToArray(typeof(BrowseElement)));
}
// release position object.
position.Dispose();
position = null;
// return elements.
return((BrowseElement[])elements.ToArray(typeof(BrowseElement)));
}
}
