Read(IEasyUAClient,UANodeArguments,UAReadParameters) Method

Reads attribute data from an OPC server. Value, status code, and timestamps are returned. Reads a Value attribute of a node, using an object that holds the node information, and a read parameters object.

Syntax

Visual Basic
C#
C++/CLI

'Declaration
 
<ExtensionAttribute()>
<NotNullAttribute()>
Public Overloads Shared Function Read( _
   ByVal client As IEasyUAClient, _
   ByVal nodeArguments As UANodeArguments, _
   ByVal readParameters As UAReadParameters _
) As UAAttributeData

'Usage
 
Dim client As IEasyUAClient
Dim nodeArguments As UANodeArguments
Dim readParameters As UAReadParameters
Dim value As UAAttributeData
 
value = IEasyUAClientExtension.Read(client, nodeArguments, readParameters)

[Extension()]
[NotNull()]
public static UAAttributeData Read( 
   IEasyUAClient client,
   UANodeArguments nodeArguments,
   UAReadParameters readParameters
)

[Extension()]
[NotNull()]
public:
static UAAttributeData^ Read( 
   IEasyUAClient^ client,
   UANodeArguments^ nodeArguments,
   UAReadParameters^ readParameters
)

Parameters

client: The client object that will perform the operation.
nodeArguments: An object that specifies the node in the OPC server.
readParameters: Read parameters, such as the maximum age of the value.

Return Value

Returns an attribute data object that stores the value of an attribute, together with status code and timestamps.

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.

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

IEasyUAClientExtension Class
IEasyUAClientExtension Members
Overload List

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