FindDirectory Method (IEasyUAFileTransfer)

Finds a directory object with the given name under the specified parent directory.

Syntax

Visual Basic
C#
C++/CLI

'Declaration
 
<CanBeNullAttribute()>
Function FindDirectory( _
   ByVal endpointDescriptor As UAEndpointDescriptor, _
   ByVal directoryNodeDescriptor As UANodeDescriptor, _
   ByVal directoryName As String _
) As UANodeDescriptor

'Usage
 
Dim instance As IEasyUAFileTransfer
Dim endpointDescriptor As UAEndpointDescriptor
Dim directoryNodeDescriptor As UANodeDescriptor
Dim directoryName As String
Dim value As UANodeDescriptor
 
value = instance.FindDirectory(endpointDescriptor, directoryNodeDescriptor, directoryName)

[CanBeNull()]
UANodeDescriptor FindDirectory( 
   UAEndpointDescriptor endpointDescriptor,
   UANodeDescriptor directoryNodeDescriptor,
   string directoryName
)

[CanBeNull()]
UANodeDescriptor^ FindDirectory( 
   UAEndpointDescriptor^ endpointDescriptor,
   UANodeDescriptor^ directoryNodeDescriptor,
   String^ directoryName
)

Parameters

endpointDescriptor: Endpoint descriptor. Identifies the OPC-UA server.
directoryNodeDescriptor: Node descriptor of the OPC UA directory.
directoryName: The name of the OPC UA directory to find.

Return Value

Returns a node descriptor of the directory object, if the directory named exists under the parent directory specified by the . Returns null otherwise.

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.

If the directoryNodeDescriptor does not denote an existing node of the OpcLabs.EasyOpc.UA.AddressSpace.Standard.UAObjectTypeIds.FileDirectoryType object type, the method throws OpcLabs.EasyOpc.UA.OperationModel.UAException. If, however, the directoryNodeDescriptor denotes an existing directory node, but the child directory named directoryName does not exist, the method returns null.

This method finds an OPC UA node 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

IEasyUAFileTransfer Interface
IEasyUAFileTransfer Members
FindFile Method
FindDirectory(IEasyUAFileTransfer,UAEndpointDescriptor,UANamedNodePath) Method
GetDirectory(IEasyUAFileTransfer,UAEndpointDescriptor,UANamedNodePath) Method
IsDirectory Method
ListDirectoryNames Method

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