OpenOrCreateStream(IEasyUAFileTransfer,UAEndpointDescriptor,UANamedNodeDescriptor,FileMode,FileAccess,Int32) Method

Opens an existing OPC UA file, or creates a new OPC UA file if one does not exist, and returns a System.IO.Stream to access the file data.

Syntax

Visual Basic
C#
C++/CLI

'Declaration
 
<ExtensionAttribute()>
<NotNullAttribute()>
Public Overloads Shared Function OpenOrCreateStream( _
   ByVal fileTransfer As IEasyUAFileTransfer, _
   ByVal endpointDescriptor As UAEndpointDescriptor, _
   ByVal fileNamedNodeDescriptor As UANamedNodeDescriptor, _
   ByVal fileMode As FileMode, _
   ByVal fileAccess As FileAccess, _
   ByVal bufferSize As Integer _
) As Stream

'Usage
 
Dim fileTransfer As IEasyUAFileTransfer
Dim endpointDescriptor As UAEndpointDescriptor
Dim fileNamedNodeDescriptor As UANamedNodeDescriptor
Dim fileMode As FileMode
Dim fileAccess As FileAccess
Dim bufferSize As Integer
Dim value As Stream
 
value = IEasyUAFileTransferExtension2.OpenOrCreateStream(fileTransfer, endpointDescriptor, fileNamedNodeDescriptor, fileMode, fileAccess, bufferSize)

[Extension()]
[NotNull()]
public static Stream OpenOrCreateStream( 
   IEasyUAFileTransfer fileTransfer,
   UAEndpointDescriptor endpointDescriptor,
   UANamedNodeDescriptor fileNamedNodeDescriptor,
   FileMode fileMode,
   FileAccess fileAccess,
   int bufferSize
)

[Extension()]
[NotNull()]
public:
static Stream^ OpenOrCreateStream( 
   IEasyUAFileTransfer^ fileTransfer,
   UAEndpointDescriptor^ endpointDescriptor,
   UANamedNodeDescriptor^ fileNamedNodeDescriptor,
   FileMode fileMode,
   FileAccess fileAccess,
   int bufferSize
)

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 stream should be opened or that should be created for the stream.
fileMode: One of the enumeration values that determines how to open or create the file.
fileAccess: A bitwise combination of the enumeration values that sets the System.IO.Stream.CanRead and System.IO.Stream.CanWrite properties of the System.IO.Stream object.
bufferSize: The buffer size in bytes.

Return Value

Returns a System.IO.Stream opened for access to the specified file.

Exceptions

Exception	Description
System.ArgumentException	One of the arguments provided to a method is not valid. 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.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.ArgumentOutOfRangeException	The value of an argument is outside the allowable range of values as defined by the invoked method. 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

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

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.

For this method to succeed if it is creating a new file, the fileNamedNodeDescriptor must contain both the named node path (of the parent directory) in the OpcLabs.EasyOpc.UA.Navigation.UANamedNodeDescriptor.NamedNodePath property, and the node name (name of the file) in the OpcLabs.EasyOpc.UA.Navigation.UANamedNodeDescriptor.NodeName property. If this method is opening an existing stream, the file can also be specified using just the final node descriptor (node of the file object) in the OpcLabs.EasyOpc.UA.Navigation.UANamedNodeDescriptor.FinalNodeDescriptor property.

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
CreateStream(IEasyUAFileTransfer,UAEndpointDescriptor,UANamedNodeDescriptor) Method
OpenOrCreateStreamWriter(IEasyUAFileTransfer,UAEndpointDescriptor,UANamedNodeDescriptor) Method
OpenStream(IEasyUAFileTransfer,UAEndpointDescriptor,UANamedNodeDescriptor) Method

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