GetExtensionFieldValue Method (IUAReadOnlyPubSubConfigurationExtension)

Gets the value of an extension field in specified published dataset.

Syntax

Visual Basic
C#
C++/CLI

'Declaration
 
<ExtensionAttribute()>
<CanBeNullAttribute()>
Public Shared Function GetExtensionFieldValue( _
   ByVal readOnlyPubSubConfiguration As IUAReadOnlyPubSubConfiguration, _
   ByVal publishedDataSetName As String, _
   ByVal dataSetFolderPath As IReadOnlyList(Of String), _
   ByVal extensionFieldQualifiedName As UAQualifiedName _
) As Object

'Usage
 
Dim readOnlyPubSubConfiguration As IUAReadOnlyPubSubConfiguration
Dim publishedDataSetName As String
Dim dataSetFolderPath As IReadOnlyList(Of String)
Dim extensionFieldQualifiedName As UAQualifiedName
Dim value As Object
 
value = IUAReadOnlyPubSubConfigurationExtension.GetExtensionFieldValue(readOnlyPubSubConfiguration, publishedDataSetName, dataSetFolderPath, extensionFieldQualifiedName)

[Extension()]
[CanBeNull()]
public static object GetExtensionFieldValue( 
   IUAReadOnlyPubSubConfiguration readOnlyPubSubConfiguration,
   string publishedDataSetName,
   IReadOnlyList<string> dataSetFolderPath,
   UAQualifiedName extensionFieldQualifiedName
)

[Extension()]
[CanBeNull()]
public:
static Object^ GetExtensionFieldValue( 
   IUAReadOnlyPubSubConfiguration^ readOnlyPubSubConfiguration,
   String^ publishedDataSetName,
   IReadOnlyList<String^>^ dataSetFolderPath,
   UAQualifiedName^ extensionFieldQualifiedName
)

Parameters

readOnlyPubSubConfiguration

OPC UA PubSub configuration (read-only).

This is typically obtained by calling OpcLabs.EasyOpc.UA.PubSub.InformationModel.EasyUAPublishSubscribeClientCore.AccessReadOnlyConfiguration, OpcLabs.EasyOpc.UA.PubSub.InformationModel.Extensions.IEasyUAPublishSubscribeClientExtension.AccessOrLoadReadOnlyConfiguration or OpcLabs.EasyOpc.UA.PubSub.InformationModel.Extensions.IEasyUAPublishSubscribeClientExtension.AccessOrLoadReadOnlyConfiguration.

The value of this parameter cannot be null (Nothing in Visual Basic).

publishedDataSetName

The name of the published dataset.

The value of this parameter cannot be null (Nothing in Visual Basic).

dataSetFolderPath

An optional path to the folder that contains the published dataset.

The value of this parameter can be null (Nothing in Visual Basic).

The individual elements of the parameter value cannot be null (Nothing in Visual Basic).

extensionFieldQualifiedName

The qualified name of the extension field.

Because the OpcLabs.EasyOpc.UA.AddressSpace.UAQualifiedName has an implicit conversion from System.String, in languages that support implicit conversion operators (such as C# or VB.NET), you can simply use a string (representing the expanded text of the qualified name) in place of this parameter, and the corresponding OPC UA qualified name will be constructed automatically. When the implicit conversion operators are not supported (such as with Python.NET), you can use the OpcLabs.EasyOpc.UA.AddressSpace.UAQualifiedName.UAQualifiedName Constructor(String) constructor instead.

The value of this parameter cannot be null (Nothing in Visual Basic).

Return Value

Returns an object that is a value of the specified extension field.

This method can return null (Nothing in Visual Basic).

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.
OpcLabs.EasyOpc.UA.OperationModel.UALogicalException	There is a logical error in the OPC UA operation. 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.

OpcLabs.EasyOpc.UA.OperationModel.UALogicalException

There is a logical error in the OPC UA operation.

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

This is an extension method (info: C#, VB.NET). In languages that have support for extensions methods (such as C# and VB.NET), you can use the extension method as if it were a regular method on the object that is its first parameter. In other languages (such as with Python.NET), you will call the extension as a static method, and pass it the object on which it acts as its first parameter.

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

IUAReadOnlyPubSubConfigurationExtension Class
IUAReadOnlyPubSubConfigurationExtension Members

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