Write(IEasyUAClient,UAEndpointDescriptor,UANodeDescriptor,UAAttributeData) Method

Writes data into a Value attribute of a node, using an endpoint descriptor and a node Id.

Syntax

Visual Basic
C#
C++/CLI

'Declaration
 
<ExtensionAttribute()>
Public Overloads Shared Function Write( _
   ByVal client As IEasyUAClient, _
   ByVal endpointDescriptor As UAEndpointDescriptor, _
   ByVal nodeDescriptor As UANodeDescriptor, _
   ByVal attributeData As UAAttributeData _
) As ValueTuple(Of Boolean,Boolean)

'Usage
 
Dim client As IEasyUAClient
Dim endpointDescriptor As UAEndpointDescriptor
Dim nodeDescriptor As UANodeDescriptor
Dim attributeData As UAAttributeData
Dim value As ValueTuple(Of Boolean,Boolean)
 
value = IEasyUAClientExtension.Write(client, endpointDescriptor, nodeDescriptor, attributeData)

[Extension()]
public static ValueTuple<bool,bool> Write( 
   IEasyUAClient client,
   UAEndpointDescriptor endpointDescriptor,
   UANodeDescriptor nodeDescriptor,
   UAAttributeData attributeData
)

[Extension()]
public:
static ValueTuple<bool,bool> Write( 
   IEasyUAClient^ client,
   UAEndpointDescriptor^ endpointDescriptor,
   UANodeDescriptor^ nodeDescriptor,
   UAAttributeData^ attributeData
)

Parameters

client

The client object that will perform the operation.

This is typically the EasyUAClient object.

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

endpointDescriptor

Endpoint descriptor. Identifies the OPC-UA server.

Because the UAEndpointDescriptor has implicit conversions from System.String and System.Uri, in languages that support implicit conversion operators (such as C# or VB.NET), you can simply use a string (representing the endpoint URL, or a so-called OPC UA endpoint descriptor string), or a System.Uri object, in place of this parameter, and the corresponding endpoint descriptor will be constructed automatically. When the implicit conversion operators are not supported (such as with Python.NET), you can use the UAEndpointDescriptor.FromString or UAEndpointDescriptor.FromUri static method instead.

Also, because the OpcLabs.EasyOpc.UA.Discovery.UAApplicationElement and OpcLabs.EasyOpc.UA.Discovery.UADiscoveryElement have an implicit conversion to UAEndpointDescriptor, in languages that support implicit conversion operators (such as C# or VB.NET), you can simply use a OpcLabs.EasyOpc.UA.Discovery.UAApplicationElement or OpcLabs.EasyOpc.UA.Discovery.UADiscoveryElement (results from OPC UA discovery) in place of this parameter, and the corresponding endpoint descriptor will be constructed automatically. When the implicit conversion operators are not supported (such as with Python.NET), you can convert a (non-null) OpcLabs.EasyOpc.UA.Discovery.UAApplicationElement or OpcLabs.EasyOpc.UA.Discovery.UADiscoveryElement to UAEndpointDescriptor using the OpcLabs.EasyOpc.UA.Discovery.UAApplicationElement.ToUAEndpointDescriptor or OpcLabs.EasyOpc.UA.Discovery.UADiscoveryElement.ToUAEndpointDescriptor method instead.

If you are using OPC Wizard (for server development), an implicit conversion from EasyUAServerCore can be used in the same way to simply pass the server object in place of this parameter, which will use its OpcLabs.EasyOpc.UA.EasyUAServerCore.EffectiveServerDescriptor property for the connection.

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

nodeDescriptor

Node descriptor. Identifies the node in OPC server's address space.

Because the UANodeDescriptor has implicit conversions from OpcLabs.EasyOpc.UA.AddressSpace.UANodeId, OpcLabs.EasyOpc.UA.AddressSpace.UANodeElement, OpcLabs.EasyOpc.UA.Navigation.UABrowsePath and System.String, in languages that support implicit conversion operators (such as C# or VB.NET), you can simply use a OpcLabs.EasyOpc.UA.AddressSpace.UANodeId object (representing the Id of the OPC UA node), a node element object (from OPC UA browsing), OpcLabs.EasyOpc.UA.Navigation.UABrowsePath object (representing OPC UA absolute browse path), or a string (with expanded node Id text) in place of this parameter, and the corresponding node descriptor will be constructed automatically. When the implicit conversion operators are not supported (such as with Python.NET), you can use the UANodeDescriptor.FromString, UANodeDescriptor.FromUABrowsePath, UANodeDescriptor.FromUANodeElement or UANodeDescriptor.FromUANodeId static method instead.

If you are using OPC Wizard (for server development), an implicit conversion from OpcLabs.EasyOpc.UA.NodeSpace.UAServerNode can be used in the same way to simply pass the server node in place of this parameter, which will use its OpcLabs.EasyOpc.UA.NodeSpace.UAServerNode.EffectiveNodeDescriptor property for the operation.

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

attributeData

Value of an attribute, together with status code and timestamps, to be written.

The value of this parameter cannot be 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.

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

You can obtain nodeDescriptor e.g. by calling one of the browsing methods on EasyUAClientCore object.

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.

Example

CSharp
PowerShell
VB.NET
Visual Basic (VB 6.0)
Python

// This example shows how to write data (a value, timestamps and status code) into a single attribute of a node.
//
// Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .
// OPC client and subscriber examples in C# on GitHub: https://github.com/OPCLabs/Examples-QuickOPC-CSharp .
// Missing some example? Ask us for it on our Online Forums, https://www.opclabs.com/forum/index ! You do not have to own
// a commercial license in order to use Online Forums, and we reply to every post.

using System;
using OpcLabs.EasyOpc.UA;
using OpcLabs.EasyOpc.UA.OperationModel;

namespace UADocExamples._EasyUAClient
{
    class Write
    {
        public static void Main1()
        {
            UAEndpointDescriptor endpointDescriptor =
                "opc.tcp://opcua.demo-this.com:51210/UA/SampleServer";
            // or "http://opcua.demo-this.com:51211/UA/SampleServer" (currently not supported)
            // or "https://opcua.demo-this.com:51212/UA/SampleServer/"

            // Instantiate the client object.
            var client = new EasyUAClient();

            Console.WriteLine("Modifying data of a node's attribute...");
            try
            {
                client.Write(endpointDescriptor, "nsu=http://test.org/UA/Data/ ;i=10221",
                    new UAAttributeData(12345, UASeverity.GoodOrSuccess, DateTime.UtcNow));

                // The target server may not support this, and in such case a failure will occur.
            }
            catch (UAException uaException)
            {
                Console.WriteLine($"*** Failure: {uaException.GetBaseException().Message}");
                return;
            }

            Console.WriteLine("Finished.");
        }
    }
}

# This example shows how to write data (a value, timestamps and status code) into a single attribute of a node.
#
# Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .
# OPC client and subscriber examples in PowerShell on GitHub: https://github.com/OPCLabs/Examples-QuickOPC-PowerShell .
# Missing some example? Ask us for it on our Online Forums, https://www.opclabs.com/forum/index ! You do not have to own
# a commercial license in order to use Online Forums, and we reply to every post.

#requires -Version 5.1
using namespace OpcLabs.EasyOpc.UA
using namespace OpcLabs.EasyOpc.UA.OperationModel

# The path below assumes that the current directory is [ProductDir]/Examples-NET/PowerShell/Windows .
Add-Type -Path "../../../Components/Opclabs.QuickOpc/net472/OpcLabs.EasyOpcUA.dll"
Add-Type -Path "../../../Components/Opclabs.QuickOpc/net472/OpcLabs.EasyOpcUAComponents.dll"

[UAEndpointDescriptor]$endpointDescriptor =
    "opc.tcp://opcua.demo-this.com:51210/UA/SampleServer"
# or "http://opcua.demo-this.com:51211/UA/SampleServer" (currently not supported)
# or "https://opcua.demo-this.com:51212/UA/SampleServer/"

# Instantiate the client object.
$client = New-Object EasyUAClient

Write-Host "Modifying data of a node's attribute..."
try {
    $client.Write($endpointDescriptor, "nsu=http://test.org/UA/Data/ ;i=10221", 
        (New-Object UAAttributeData(12345, [UASeverity]::GoodOrSuccess, [DateTime]::UtcNow)))

    # The target server may not support this, and in such case a failure will occur.
}
catch [UAException] {
    Write-Host "*** Failure: $($PSItem.Exception.GetBaseException().Message)"
    return
}

Write-Host "Finished."

' This example shows how to write data (a value, timestamps and status code) into a single attribute of a node.
'
' Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .
' OPC client and subscriber examples in VB.NET on GitHub: https://github.com/OPCLabs/Examples-QuickOPC-VBNET .
' Missing some example? Ask us for it on our Online Forums, https://www.opclabs.com/forum/index ! You do not have to own
' a commercial license in order to use Online Forums, and we reply to every post.

Imports OpcLabs.EasyOpc.UA
Imports OpcLabs.EasyOpc.UA.OperationModel

Namespace _EasyUAClient
    Friend Class Write
        Public Shared Sub Main1()

            ' Define which server we will work with.
            Dim endpointDescriptor As UAEndpointDescriptor =
                    "opc.tcp://opcua.demo-this.com:51210/UA/SampleServer"
            ' or "http://opcua.demo-this.com:51211/UA/SampleServer" (currently not supported)
            ' or "https://opcua.demo-this.com:51212/UA/SampleServer/"

            ' Instantiate the client object
            Dim client = New EasyUAClient()

            Try
                ' Modify data of a node's attribute
                client.Write(endpointDescriptor, "nsu=http://test.org/UA/Data/ ;i=10221",
                                   New UAAttributeData(12345, UASeverity.GoodOrSuccess, Date.UtcNow)) ' or "opc.tcp://opcua.demo-this.com:51210/UA/SampleServer"

                ' The target server may not support this, and in such case a failure will occur.
            Catch uaException As UAException
                Console.WriteLine("*** Failure: {0}", uaException.GetBaseException().Message)
            End Try
        End Sub
    End Class
End Namespace

REM This example shows how to write data (a value, timestamps and status code)
REM into a single attribute of a node.
REM
REM Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .
REM OPC client and subscriber examples in Visual Basic on GitHub: https://github.com/OPCLabs/Examples-QuickOPC-VB .
REM Missing some example? Ask us for it on our Online Forums, https://www.opclabs.com/forum/index ! You do not have to own
REM a commercial license in order to use Online Forums, and we reply to every post.

Public Sub Write_Main_Command_Click()
    OutputText = ""

    Const GoodOrSuccess = 0

    ' Instantiate the client object
    Dim Client As New EasyUAClient

    ' Modify data of a node's attribute
    Dim StatusCode As New UAStatusCode
    StatusCode.Severity = GoodOrSuccess
    Dim AttributeData As New UAAttributeData
    AttributeData.SetValue 12345
    Set AttributeData.StatusCode = StatusCode
    AttributeData.SourceTimestamp = Now()
    
    ' Perform the operation
    On Error Resume Next
    Call Client.Write("opc.tcp://opcua.demo-this.com:51210/UA/SampleServer", "nsu=http://test.org/UA/Data/ ;i=10221", AttributeData)
    If Err.Number <> 0 Then
        OutputText = OutputText & "*** Failure: " & Err.Source & ": " & Err.Description & vbCrLf
        Exit Sub
    End If
    On Error GoTo 0
End Sub

# This example shows how to write data (a value, timestamps and status code) into a single attribute of a node.
#
# Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .
# OPC client and subscriber examples in Python on GitHub: https://github.com/OPCLabs/Examples-QuickOPC-Python .
# Missing some example? Ask us for it on our Online Forums, https://www.opclabs.com/forum/index ! You do not have to own
# a commercial license in order to use Online Forums, and we reply to every post.
# The QuickOPC package is needed. Install it using "pip install opclabs_quickopc".
import opclabs_quickopc

# Import .NET namespaces.
from System import *
from OpcLabs.EasyOpc.UA import *
from OpcLabs.EasyOpc.UA.OperationModel import *


endpointDescriptor = UAEndpointDescriptor('opc.tcp://opcua.demo-this.com:51210/UA/SampleServer')
# or 'http://opcua.demo-this.com:51211/UA/SampleServer' (currently not supported)
# or 'https://opcua.demo-this.com:51212/UA/SampleServer/'

# Instantiate the client object
client = EasyUAClient()

print("Modifying data of a node's attribute...")
try:
    IEasyUAClientExtension.Write(client,
        endpointDescriptor,
        UANodeDescriptor('nsu=http://test.org/UA/Data/ ;i=10221'),
        UAAttributeData(12345, UAStatusCode(UASeverity.GoodOrSuccess), DateTime.UtcNow))
except UAException as uaException:
    print('*** Failure: ' + uaException.GetBaseException().Message)
    exit()

print('Finished.')

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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Missing some example? Ask us for it on our Online Forums! You do not have to own a commercial license in order to use Online Forums, and we reply to every post.