ListDirectoryNames Method (EasyUAFileTransferClientCore)

Obtains names of directories under the specified parent OPC UA directory.

Syntax

Visual Basic
C#
C++/CLI

'Declaration
 
Public Function ListDirectoryNames( _
   ByVal endpointDescriptor As UAEndpointDescriptor, _
   ByVal directoryNodeDescriptor As UANodeDescriptor _
) As StringCollection

'Usage
 
Dim instance As EasyUAFileTransferClientCore
Dim endpointDescriptor As UAEndpointDescriptor
Dim directoryNodeDescriptor As UANodeDescriptor
Dim value As StringCollection
 
value = instance.ListDirectoryNames(endpointDescriptor, directoryNodeDescriptor)

public StringCollection ListDirectoryNames( 
   UAEndpointDescriptor endpointDescriptor,
   UANodeDescriptor directoryNodeDescriptor
)

public:
StringCollection^ ListDirectoryNames( 
   UAEndpointDescriptor^ endpointDescriptor,
   UANodeDescriptor^ directoryNodeDescriptor
)

Parameters

endpointDescriptor: Endpoint descriptor. Identifies the OPC-UA server.
directoryNodeDescriptor: Node descriptor of the OPC UA directory.

Return Value

Returns a collection of names of directories under the parent directory specified by the .

Exceptions

Exception Description

Exception	Description
System.ArgumentNullException	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.
OpcLabs.EasyOpc.UA.OperationModel.UAException	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.

System.ArgumentNullException

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.

OpcLabs.EasyOpc.UA.OperationModel.UAException

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 directoryNodeDescriptor must be an existing node in the server, of object type OpcLabs.EasyOpc.UA.AddressSpace.Standard.UAObjectTypeIds.FileDirectoryType.

This method lists OPC UA nodes of object type FileDirectoryType, which is described here: . Sub-directories are referenced from their parent directory using the OpcLabs.EasyOpc.UA.AddressSpace.Standard.UAReferenceTypeIds.Organizes reference type.

Requirements

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

Reference

EasyUAFileTransferClientCore Class
EasyUAFileTransferClientCore Members
ListFileNames Method
BrowseDirectories(IEasyUAFileTransfer,UAEndpointDescriptor,UANamedNodePath) Method
EnumerateDirectories(IEasyUAFileTransfer,UAEndpointDescriptor,UANamedNodePath) Method
ListDirectoryNames(IEasyUAFileTransfer,UAEndpointDescriptor,UANamedNodePath) Method
ListFileAndDirectoryNames(IEasyUAFileTransfer,UAEndpointDescriptor,UANamedNodePath) Method

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