OpenStreamReader(IEasyUAFileTransfer,UAEndpointDescriptor,UANamedNodeDescriptor) Method

Opens an existing OPC UA text file for reading via System.IO.StreamReader.

Syntax

Visual Basic
C#
C++/CLI

'Declaration
 
<ExtensionAttribute()>
<NotNullAttribute()>
Public Overloads Shared Function OpenStreamReader( _
   ByVal fileTransfer As IEasyUAFileTransfer, _
   ByVal endpointDescriptor As UAEndpointDescriptor, _
   ByVal fileNamedNodeDescriptor As UANamedNodeDescriptor _
) As StreamReader

'Usage
 
Dim fileTransfer As IEasyUAFileTransfer
Dim endpointDescriptor As UAEndpointDescriptor
Dim fileNamedNodeDescriptor As UANamedNodeDescriptor
Dim value As StreamReader
 
value = IEasyUAFileTransferExtension2.OpenStreamReader(fileTransfer, endpointDescriptor, fileNamedNodeDescriptor)

[Extension()]
[NotNull()]
public static StreamReader OpenStreamReader( 
   IEasyUAFileTransfer fileTransfer,
   UAEndpointDescriptor endpointDescriptor,
   UANamedNodeDescriptor fileNamedNodeDescriptor
)

[Extension()]
[NotNull()]
public:
static StreamReader^ OpenStreamReader( 
   IEasyUAFileTransfer^ fileTransfer,
   UAEndpointDescriptor^ endpointDescriptor,
   UANamedNodeDescriptor^ fileNamedNodeDescriptor
)

Parameters

fileTransfer: The OPC UA file transfer object that will perform the operation.
endpointDescriptor: Endpoint descriptor. Identifies the OPC-UA server.
fileNamedNodeDescriptor: The named node descriptor of the file on which the text file reader should be opened.

Return Value

Returns a System.IO.StreamReader on the specified file.

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.
System.IO.FileNotFoundException	An attempt to access a file that does not exist on disk has failed. 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.IO.IOException	An I/O error has occurred. 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.

System.IO.FileNotFoundException

An attempt to access a file that does not exist on disk has failed.

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.IO.IOException

An I/O error has occurred.

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

CAUTION: This method does not throw the usual OpcLabs.EasyOpc.UA.OperationModel.UAException. Instead, an System.IO.IOException is thrown in case of an error during the operation.

See OPC UA File Transfer internals for information about Stream buffering.

Recommendation: Whenever possible, do not use this method directly, and use a higher-level abstraction instead. You can obtain a file provider (using GetFileProvider2), and make use of its methods, and methods available on the directory contents (obtained using Microsoft.Extensions.FileProviders.IFileProvider.GetDirectoryContents(System.String)) or file info (obtained using Microsoft.Extensions.FileProviders.IFileProvider.GetFileInfo(System.String)).

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

IEasyUAFileTransferExtension2 Class
IEasyUAFileTransferExtension2 Members
Overload List
OpenOrCreateStreamWriter(IEasyUAFileTransfer,UAEndpointDescriptor,UANamedNodeDescriptor) Method
OpenStream(IEasyUAFileTransfer,UAEndpointDescriptor,UANamedNodeDescriptor) Method
OpenStreamWriter(IEasyUAFileTransfer,UAEndpointDescriptor,UANamedNodeDescriptor) Method

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