IsDirectory Method (IEasyUAFileTransfer)

Determines whether the specified node represents an OPC UA directory.

Syntax

Visual Basic
C#
C++/CLI

'Declaration
 
Function IsDirectory( _
   ByVal endpointDescriptor As UAEndpointDescriptor, _
   ByVal nodeDescriptor As UANodeDescriptor _
) As Boolean

'Usage
 
Dim instance As IEasyUAFileTransfer
Dim endpointDescriptor As UAEndpointDescriptor
Dim nodeDescriptor As UANodeDescriptor
Dim value As Boolean
 
value = instance.IsDirectory(endpointDescriptor, nodeDescriptor)

bool IsDirectory( 
   UAEndpointDescriptor endpointDescriptor,
   UANodeDescriptor nodeDescriptor
)

bool IsDirectory( 
   UAEndpointDescriptor^ endpointDescriptor,
   UANodeDescriptor^ nodeDescriptor
)

Parameters

endpointDescriptor: Endpoint descriptor. Identifies the OPC-UA server.
nodeDescriptor: Node descriptor of the node to be tested.

Return Value

Returns true if the node specified by the represents an OPC UA directory, i.e. it is an object of type OpcLabs.EasyOpc.UA.AddressSpace.Standard.UAObjectTypeIds.FileDirectoryType. Returns false 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

This method tests for an OPC UA node of object type FileDirectoryType, which is described here: .

In order to allow for efficient caching, this method is allowed to return a false positive, i.e. you may sometimes receive true when the object does not exist. Attempts to make operations on such object will still fail. The method will always return false when the object does not exist.

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
FindDirectory Method
IsDirectory(IEasyUAFileTransfer,UAEndpointDescriptor,UANamedNodePath) Method
IsFileOrDirectory(IEasyUAFileTransfer,UAEndpointDescriptor,UANodeDescriptor) Method
IsRootDirectory Method
IsFile Method

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