QuickOPC User's Guide and Reference
FindDirectory(IEasyUAFileTransfer,UAEndpointDescriptor,UANamedNodePath) Method



OpcLabs.EasyOpcUA Assembly > OpcLabs.EasyOpc.UA.FileTransfer Namespace > IEasyUAFileTransferExtension Class > FindDirectory Method : FindDirectory(IEasyUAFileTransfer,UAEndpointDescriptor,UANamedNodePath) Method
The OPC UA file transfer object that will perform the operation.
Endpoint descriptor. Identifies the OPC-UA server.
The named node path to test.
Finds a directory object under the specified parent directory.
Syntax
'Declaration
 
<ExtensionAttribute()>
<CanBeNullAttribute()>
Public Overloads Shared Function FindDirectory( _
   ByVal fileTransfer As IEasyUAFileTransfer, _
   ByVal endpointDescriptor As UAEndpointDescriptor, _
   ByVal namedNodePath As UANamedNodePath _
) As UANodeDescriptor
'Usage
 
Dim fileTransfer As IEasyUAFileTransfer
Dim endpointDescriptor As UAEndpointDescriptor
Dim namedNodePath As UANamedNodePath
Dim value As UANodeDescriptor
 
value = IEasyUAFileTransferExtension.FindDirectory(fileTransfer, endpointDescriptor, namedNodePath)

Parameters

fileTransfer
The OPC UA file transfer object that will perform the operation.
endpointDescriptor
Endpoint descriptor. Identifies the OPC-UA server.
namedNodePath
The named node path to test.

Return Value

Returns a node descriptor of the directory object, if the directory was found. Returns null otherwise.
Exceptions
ExceptionDescription

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.

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

If the OpcLabs.EasyOpc.UA.Navigation.UANamedNodePath.BaseNodeDescriptor of the namedNodePath 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 OpcLabs.EasyOpc.UA.Navigation.UANamedNodePath.BaseNodeDescriptor of the namedNodePath denotes an existing directory node, but any of the child directories in the OpcLabs.EasyOpc.UA.Navigation.UANamedNodePath.PathElements of the namedNodePath does not exist, the method returns null.

Requirements

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

See Also