FindRootDirectory Method

Finds a root directory of the specified OPC UA file or directory object.

Syntax

Visual Basic
C#
C++/CLI

'Declaration
 
<ExtensionAttribute()>
<CanBeNullAttribute()>
Public Shared Function FindRootDirectory( _
   ByVal fileTransfer As IEasyUAFileTransfer, _
   ByVal endpointDescriptor As UAEndpointDescriptor, _
   ByVal fileOrDirectoryNodeDescriptor As UANodeDescriptor _
) As UANodeDescriptor

'Usage
 
Dim fileTransfer As IEasyUAFileTransfer
Dim endpointDescriptor As UAEndpointDescriptor
Dim fileOrDirectoryNodeDescriptor As UANodeDescriptor
Dim value As UANodeDescriptor
 
value = IEasyUAFileTransferExtension.FindRootDirectory(fileTransfer, endpointDescriptor, fileOrDirectoryNodeDescriptor)

[Extension()]
[CanBeNull()]
public static UANodeDescriptor FindRootDirectory( 
   IEasyUAFileTransfer fileTransfer,
   UAEndpointDescriptor endpointDescriptor,
   UANodeDescriptor fileOrDirectoryNodeDescriptor
)

[Extension()]
[CanBeNull()]
public:
static UANodeDescriptor^ FindRootDirectory( 
   IEasyUAFileTransfer^ fileTransfer,
   UAEndpointDescriptor^ endpointDescriptor,
   UANodeDescriptor^ fileOrDirectoryNodeDescriptor
)

Parameters

fileTransfer: The OPC UA file transfer object that will perform the operation.
endpointDescriptor: Endpoint descriptor. Identifies the OPC-UA server.
fileOrDirectoryNodeDescriptor: The directory node descriptor of the file or directory for which the root directory should be found.

Return Value

Returns a node descriptor of the root directory object, if the root directory was found. 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

In typical file systems, it is always possible to find a root. Also, in them, a root for the root is the root itself. In OPC UA file transfer, however, files can also appear standalone, and such files have no associated parent or root directory.

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

IEasyUAFileTransferExtension Class
IEasyUAFileTransferExtension Members
FindRootAndPath Method
GetRootDirectory Method
IsRootDirectory Method

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