OPC Studio User's Guide and Reference
BrowseTree(IEasyUAClient,UAEndpointDescriptor,UANodeDescriptor,UABrowseParameters,Predicate<UANodeElement>) Method



OpcLabs.EasyOpcUA Assembly > OpcLabs.EasyOpc.UA.Extensions Namespace > IEasyUAClientExtension2 Class > BrowseTree Method : BrowseTree(IEasyUAClient,UAEndpointDescriptor,UANodeDescriptor,UABrowseParameters,Predicate<UANodeElement>) Method
The client object that will perform the operation.
Endpoint descriptor. Identifies the OPC-UA server.
Starting node descriptor. Identifies the node in OPC server's address space.
Browse parameters such as node classes and reference types to be returned.
The predicate specifying which nodes will be allowed into the traversal.
Allows to traverse through OPC UA address space nodes under the specified node, using given browse parameters, and allowing only nodes that fulfill a specified predicate into the traversal.
Syntax

Parameters

client
The client object that will perform the operation.
endpointDescriptor
Endpoint descriptor. Identifies the OPC-UA server.
nodeDescriptor
Starting node descriptor. Identifies the node in OPC server's address space.
browseParameters
Browse parameters such as node classes and reference types to be returned.
nodeElementPredicate
The predicate specifying which nodes will be allowed into the traversal.

Return Value

Returns an enumerator of tree positions that will traverse through all nodes specified.
Exceptions
ExceptionDescription

A null reference (Nothing in Visual Basic) is passed to a method that does not accept it as a valid argument.

This is a usage error, i.e. it will never occur (the exception will not be thrown) in a correctly written program. Your code should not catch this exception.

Remarks

If you want to enumerate through a sequence of the tree nodes, convert the result to a sequence using the OpcLabs.BaseLib.Graphs.Extensions.ITreeTraversableExtension.ToEnumerable<T> method.

The method automatically prevents recursion into nodes that have already been traversed.

The root position in a tree will correspond to the specified starting node. The OpcLabs.EasyOpc.UA.Graphs.UANodeTreePosition object for the root is special one, in that from its OpcLabs.EasyOpc.UA.AddressSpace.UANodeElement properties, only its NodeId is filled in.

You can obtain nodeDescriptor e.g. by calling one of the browsing methods on OpcLabs.EasyOpc.UA.EasyUAClientCore object.

Requirements

Target Platforms: .NET Framework: Windows 10 (selected versions), Windows 11 (selected versions), Windows Server 2016, Windows Server 2022; .NET: Linux, macOS, Microsoft Windows

See Also