OPC Studio User's Guide and Reference
ListDirectoryNames(IEasyUAFileTransfer,UAEndpointDescriptor,UANamedNodePath) Method



OpcLabs.EasyOpcUA Assembly > OpcLabs.EasyOpc.UA.FileTransfer Namespace > IEasyUAFileTransferExtension Class > ListDirectoryNames Method : ListDirectoryNames(IEasyUAFileTransfer,UAEndpointDescriptor,UANamedNodePath) Method
The OPC UA file transfer object that will perform the operation.
Endpoint descriptor. Identifies the OPC-UA server.
A named node path of the OPC UA directory.
Obtains names of directories under the specified OPC UA directory.
Syntax

Parameters

fileTransfer
The OPC UA file transfer object that will perform the operation.
endpointDescriptor
Endpoint descriptor. Identifies the OPC-UA server.
directoryNamedNodePath
A named node path of the OPC UA directory.

Return Value

Returns a tuple consisting of the resolved inner directory node descriptor, and a collection of names of the directories under the specified OPC UA directory.
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.

The OPC UA operation has failed. This operation exception in uniformly used to allow common handling of various kinds of errors. The System.Exception.InnerException always contains information about the actual error cause.

This is an operation error that depends on factors external to your program, and thus cannot be always avoided. Your code must handle it appropriately.

Remarks

The directoryNamedNodePath must refer to an existing node in the server, of object type OpcLabs.EasyOpc.UA.AddressSpace.Standard.UAObjectTypeIds.FileDirectoryType.

If you need the node descriptors (node IDs) of the directories, use the BrowseDirectories(IEasyUAFileTransfer,UAEndpointDescriptor,UANamedNodePath)method.

Recommendation: Whenever possible, do not use this method directly, and use a higher-level abstraction instead. See e.g. the GetDirectoryContents2(IEasyUAFileTransfer,UAEndpointDescriptor,UANamedNodePath) method, which allows you to obtain an object that can be enumerated for files and directories underneath, in a way that is generic and not tied to OPC UA specifics.

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