EnumerateDirectories(IEasyUAFileTransfer,UAEndpointDescriptor,UANamedNodePath) Method

Enumerates directories under the specified OPC UA directory.

Syntax

[Extension()]
public static ValueTuple<UANodeDescriptor,IEnumerable<KeyValuePair<string,UANodeDescriptor>>> EnumerateDirectories( 
   IEasyUAFileTransfer fileTransfer,
   UAEndpointDescriptor endpointDescriptor,
   UANamedNodePath directoryNamedNodePath
)

[Extension()]
public:
static ValueTuple<UANodeDescriptor^,IEnumerable<KeyValuePair<String^,UANodeDescriptor^>>^> EnumerateDirectories( 
   IEasyUAFileTransfer^ fileTransfer,
   UAEndpointDescriptor^ endpointDescriptor,
   UANamedNodePath^ directoryNamedNodePath
)

'Declaration
 
<ExtensionAttribute()>
Public Overloads Shared Function EnumerateDirectories( _
   ByVal fileTransfer As IEasyUAFileTransfer, _
   ByVal endpointDescriptor As UAEndpointDescriptor, _
   ByVal directoryNamedNodePath As UANamedNodePath _
) As ValueTuple(Of UANodeDescriptor,IEnumerable(Of KeyValuePair(Of String,UANodeDescriptor)))

'Usage
 
Dim fileTransfer As IEasyUAFileTransfer
Dim endpointDescriptor As UAEndpointDescriptor
Dim directoryNamedNodePath As UANamedNodePath
Dim value As ValueTuple(Of UANodeDescriptor,IEnumerable(Of KeyValuePair(Of String,UANodeDescriptor)))
 
value = IEasyUAFileTransferExtension.EnumerateDirectories(fileTransfer, endpointDescriptor, directoryNamedNodePath)

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 sequence of names and node descriptors of the directories under the specified OPC UA directory.

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

If you need the directory names, use the ListDirectoryNames(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

Reference

IEasyUAFileTransferExtension Class
IEasyUAFileTransferExtension Members
Overload List
BrowseDirectories(IEasyUAFileTransfer,UAEndpointDescriptor,UANamedNodePath) Method
EnumerateFiles(IEasyUAFileTransfer,UAEndpointDescriptor,UANamedNodePath) Method
ListDirectoryNames(IEasyUAFileTransfer,UAEndpointDescriptor,UANamedNodePath) Method

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