private OpcDaBrowseElement CreateBranchBrowseElement(string name)
{
return(new OpcDaBrowseElement
{
Name = name,
HasChildren = true,
IsItem = false,
ItemId = OpcBrowseServerAddressSpace.TryGetItemId(name)
});
}
public static string TryGetItemId(this OpcBrowseServerAddressSpace opcBrowseServerAddressSpace, string itemName)
{
try
{
return(opcBrowseServerAddressSpace.GetItemId(itemName));
}
catch (Exception ex)
{
return(null);
}
}
private void MoveToRoot()
{
try
{
for (int i = 0; i < MaxDepth; ++i)
{
// will throw if we aleady at root
OpcBrowseServerAddressSpace.ChangeBrowsePosition(OPCBROWSEDIRECTION.OPC_BROWSE_UP);
}
}
catch (COMException ex)
{
if (ex.ErrorCode == HRESULT.E_FAIL) // E_FAIL when change position on root element;
{
return;
}
throw;
}
}
protected override void ChangeBrowsePositionTo(string itemId)
{
IEnumerable <string> path;
if (!_itemIdToPath.TryGetValue(itemId, out path))
{
throw new ArgumentException("Item not discovered yet. In OPC DA 1.X all parent branches should be expanded before expanding the element.", "itemId");
}
MoveToRoot();
if (String.IsNullOrEmpty(itemId)) // Already at root
{
return;
}
// Browse down using path
foreach (var itemName in path)
{
OpcBrowseServerAddressSpace.ChangeBrowsePosition(OPCBROWSEDIRECTION.OPC_BROWSE_DOWN, itemName);
}
_currentPath = path;
}
protected virtual void ChangeBrowsePositionTo(string itemId)
{
OpcBrowseServerAddressSpace.ChangeBrowsePosition(OPCBROWSEDIRECTION.OPC_BROWSE_TO, itemId);
}
private OpcDaBrowseElement[] GetElementsImpl(string itemId, OpcDaElementFilter filter)
{
IEnumerable <OpcDaBrowseElement> elements;
var namespaceType = OpcBrowseServerAddressSpace.Organization;
VarEnum dataTypeFilter = TypeConverter.ToVarEnum(filter.DataType);
switch (namespaceType)
{
case OpcDaNamespaceType.Hierarchial:
ChangeBrowsePositionTo(itemId);
switch (filter.ElementType)
{
case OpcDaBrowseFilter.All:
var branches = OpcBrowseServerAddressSpace.BrowseOpcItemIds(OpcDaBrowseType.Branch,
filter.Name, dataTypeFilter,
filter.AccessRights)
.Select(CreateBranchBrowseElement);
var leafs = OpcBrowseServerAddressSpace.BrowseOpcItemIds(OpcDaBrowseType.Leaf, filter.Name,
dataTypeFilter,
filter.AccessRights)
.Select(CreateLeafBrowseElement);
elements = branches.Union(leafs);
break;
case OpcDaBrowseFilter.Branches:
elements = OpcBrowseServerAddressSpace.BrowseOpcItemIds(OpcDaBrowseType.Branch, filter.Name,
dataTypeFilter,
filter.AccessRights)
.Select(CreateBranchBrowseElement);
break;
case OpcDaBrowseFilter.Items:
elements = OpcBrowseServerAddressSpace.BrowseOpcItemIds(OpcDaBrowseType.Leaf, filter.Name,
dataTypeFilter,
filter.AccessRights)
.Select(CreateLeafBrowseElement);
break;
default:
throw new ArgumentOutOfRangeException();
}
break;
case OpcDaNamespaceType.Flat:
if (filter.ElementType == OpcDaBrowseFilter.Branches) // no branches in flat namespace
{
elements = Enumerable.Empty <OpcDaBrowseElement>();
}
else
{
elements = OpcBrowseServerAddressSpace.BrowseOpcItemIds(OpcDaBrowseType.Flat, filter.Name,
dataTypeFilter,
filter.AccessRights)
.Select(CreateLeafBrowseElement);
}
break;
default:
throw new ArgumentOutOfRangeException();
}
return(elements.ToArray());
}
