DeleteIfExists(IEasyUAFileTransfer,UAEndpointDescriptor,UANodeDescriptor,String) Method

Deletes an OPC UA file or directory if it exists (does nothing if the file or directory does not exist).

Syntax

Visual Basic
C#
C++/CLI

'Declaration
 
<ExtensionAttribute()>
Public Overloads Shared Function DeleteIfExists( _
   ByVal fileTransfer As IEasyUAFileTransfer, _
   ByVal endpointDescriptor As UAEndpointDescriptor, _
   ByVal directoryNodeDescriptor As UANodeDescriptor, _
   ByVal existingFileOrDirectoryName As String _
) As Boolean

'Usage
 
Dim fileTransfer As IEasyUAFileTransfer
Dim endpointDescriptor As UAEndpointDescriptor
Dim directoryNodeDescriptor As UANodeDescriptor
Dim existingFileOrDirectoryName As String
Dim value As Boolean
 
value = IEasyUAFileTransferExtension.DeleteIfExists(fileTransfer, endpointDescriptor, directoryNodeDescriptor, existingFileOrDirectoryName)

[Extension()]
public static bool DeleteIfExists( 
   IEasyUAFileTransfer fileTransfer,
   UAEndpointDescriptor endpointDescriptor,
   UANodeDescriptor directoryNodeDescriptor,
   string existingFileOrDirectoryName
)

[Extension()]
public:
static bool DeleteIfExists( 
   IEasyUAFileTransfer^ fileTransfer,
   UAEndpointDescriptor^ endpointDescriptor,
   UANodeDescriptor^ directoryNodeDescriptor,
   String^ existingFileOrDirectoryName
)

Parameters

fileTransfer: The OPC UA file transfer object that will perform the operation.
endpointDescriptor: Endpoint descriptor. Identifies the OPC-UA server.
directoryNodeDescriptor: Node descriptor of the OPC UA directory.
existingFileOrDirectoryName: A name of the OPC UA file or directory to delete.

Return Value

Returns true if the file or directory existed and has been deleted; returns false if the file or directory does not exist.

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

Recommendation: Whenever possible, do not use this method directly, and use a higher-level abstraction instead. See e.g. the GetWritableFileInfo(IEasyUAFileTransfer,UAEndpointDescriptor,UANamedNodeDescriptor) and GetWritableDirectoryContents(IEasyUAFileTransfer,UAEndpointDescriptor,UANamedNodePath) methods, which allow you to obtain objects that can be used to manage files and directories, 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
Delete Method
Delete Method

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