QuickOPC User's Guide and Reference
WriteValueList Method (_EasyUAClient)
Example 



OpcLabs.EasyOpcUA Assembly > OpcLabs.EasyOpc.UA.ComTypes Namespace > _EasyUAClient Interface : WriteValueList Method
Writes values into multiple attributes, using array of argument objects as an input (status codes and timestamps are not written).
Syntax
'Declaration
 
<ElementsNotNullAttribute()>
<NotNullAttribute()>
Function WriteValueList( _
   ByVal writeValueArgumentsList As IList _
) As _ElasticVector
'Usage
 
Dim instance As _EasyUAClient
Dim writeValueArgumentsList As IList
Dim value As _ElasticVector
 
value = instance.WriteValueList(writeValueArgumentsList)
[ElementsNotNull()]
[NotNull()]
_ElasticVector WriteValueList( 
   IList writeValueArgumentsList
)
[ElementsNotNull()]
[NotNull()]
_ElasticVector^ WriteValueList( 
   IList^ writeValueArgumentsList
) 

Parameters

writeValueArgumentsList

Return Value

Array of OpcLabs.EasyOpc.UA.OperationModel.UAWriteResult. The method returns an array of OpcLabs.EasyOpc.UA.OperationModel.UAWriteResult objects. The indices of elements in the output array are the same as those in the input arrays.
Exceptions
ExceptionDescription

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.

Remarks

The size of the input array will become the size of the output array. The element positions (indices) in the output array are the same as in the input array.

This method does not throw an exception in case of OPC operation failures. Instead, the eventual exception related to each item is returned in Exception property of each returned OpcLabs.EasyOpc.UA.OperationModel.UAWriteResult element.

 

This is a multiple-operation method. In a properly written program, it does not throw any exceptions. You should therefore not put try/catch statements or similar constructs around calls to this method. The only exceptions thrown by this method are for usage errors, i.e. when your code violates the usage contract of the method, such as passing in invalid arguments or calling the method when the state of the object does not allow it. Any operation-related errors (i.e. errors that depend on external conditions that your code cannot reliably check) are indicated in the result objects returned by the method. For more information, see Multiple-operation Methods and Do not catch any exceptions with asynchronous or multiple-operation methods.

This method uses lists instead of arrays.

Example

.NET

.NET

COM

// This example shows how to write values into 3 nodes at once.

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

namespace UADocExamples._EasyUAClient
{
    partial class WriteMultipleValues
    {
        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();

            // Modify value of a node
            client.WriteMultipleValues(new[]
                {
                    new UAWriteValueArguments(endpointDescriptor, "nsu=http://test.org/UA/Data/ ;i=10221", 23456),
                    new UAWriteValueArguments(endpointDescriptor, "nsu=http://test.org/UA/Data/ ;i=10226", 2.34567890),
                    new UAWriteValueArguments(endpointDescriptor, "nsu=http://test.org/UA/Data/ ;i=10227", "ABC")
                });
            // Production code would check the success of the operation. See separate example for that.
        }
    }
}
# This example shows how to write values into 3 nodes at once.

# The QuickOPC package is needed. Install it using "pip install opclabs_quickopc".
import opclabs_quickopc

# Import .NET namespaces.
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 values of nodes...')
writeResultArray = IEasyUAClientExtension.WriteMultipleValues(client, [
    UAWriteValueArguments(endpointDescriptor, UANodeDescriptor('nsu=http://test.org/UA/Data/ ;i=10221'), 23456),
    UAWriteValueArguments(endpointDescriptor, UANodeDescriptor('nsu=http://test.org/UA/Data/ ;i=10226'), 2.34567890),
    UAWriteValueArguments(endpointDescriptor, UANodeDescriptor('nsu=http://test.org/UA/Data/ ;i=10227'), 'ABC'),
    ])

# Production code would check the success of the operation. See separate example for that.

print()
print('Finished.')
' This example shows how to write values into 3 nodes at once.

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

Namespace _EasyUAClient
    Partial Friend Class WriteMultipleValues
        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()

            ' Modify value of a node
            client.WriteMultipleValues(New UAWriteValueArguments() _
                { _
                    New UAWriteValueArguments(endpointDescriptor, "nsu=http://test.org/UA/Data/ ;i=10221", 23456), _
                    New UAWriteValueArguments(endpointDescriptor, "nsu=http://test.org/UA/Data/ ;i=10226", 2.3456789), _
                    New UAWriteValueArguments(endpointDescriptor, "nsu=http://test.org/UA/Data/ ;i=10227", "ABC") _
                } _
             )
            ' Production code would check the success of the operation. See separate example for that.
        End Sub
    End Class
End Namespace
// This example shows how to write values into 3 nodes at once, test for success of each write and display the exception 
// message in case of failure.

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

namespace UADocExamples._EasyUAClient
{
    partial class WriteMultipleValues
    {
        public static void TestSuccess()
        {
            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 values of nodes...");
            OperationResult[] operationResultArray = client.WriteMultipleValues(new[]
                {
                    new UAWriteValueArguments(endpointDescriptor, "nsu=http://test.org/UA/Data/ ;i=10221", 23456),
                    new UAWriteValueArguments(endpointDescriptor, "nsu=http://test.org/UA/Data/ ;i=10226", 
                        "This string cannot be converted to Double"),
                    new UAWriteValueArguments(endpointDescriptor, "nsu=http://test.org/UA/Data/ ;s=UnknownNode", "ABC")
                });

            for (int i = 0; i < operationResultArray.Length; i++)
                if (operationResultArray[i].Succeeded)
                    Console.WriteLine($"Result {i}: success");
                else
                    Console.WriteLine($"Result {i}: {operationResultArray[i].Exception.GetBaseException().Message}");


            // Example output:
            //
            //Modifying values of nodes...
            //Result 0: success
            //Result 1: Input string was not in a correct format.
            //+ Attempting to change an object of type "System.String" to type "System.Double".
            //+ The specified original value (string) was "This string cannot be converted to Double".
            //+ The node descriptor used was: NodeId="nsu=http://test.org/UA/Data/ ;i=10226".
            //+ The client method called (or event/callback invoked) was 'WriteMultiple[3]'.
            //Result 2: The status of the OPC-UA attribute data is not Good. The actual status is 'BadNodeIdUnknown'.
            //+ During writing or method calls, readings may occur when value type is not specified.
            //+ The node descriptor used was: NodeId="nsu=http://test.org/UA/Data/ ;s=UnknownNode".
            //+ The client method called (or event/callback invoked) was 'WriteMultiple[3]'.
        }
    }
}
# This example shows how to write values into 3 nodes at once, test for success of each write and display the exception 
# message in case of failure.

#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 values of nodes..."
$operationResultArray = $client.WriteMultipleValues([UAWriteValueArguments[]]@(
        (New-Object UAWriteValueArguments($endpointDescriptor, "nsu=http://test.org/UA/Data/ ;i=10221", 23456)),
        (New-Object UAWriteValueArguments($endpointDescriptor, "nsu=http://test.org/UA/Data/ ;i=10226", 
            "This string cannot be converted to Double")),
        (New-Object UAWriteValueArguments($endpointDescriptor, "nsu=http://test.org/UA/Data/ ;s=UnknownNode", "ABC"))
    ))

for ($i = 0; $i -lt $operationResultArray.Length; $i++) {
    if ($operationResultArray[$i].Succeeded) {
        Write-Host "Result $($i): success"
    }
    else {
        Write-Host "Result $($i): $($operationResultArray[$i].Exception.GetBaseException().Message)"
    }
}


# Example output:
#
#Modifying values of nodes...
#Result 0: success
#Result 1: Input string was not in a correct format.
#+ Attempting to change an object of type "System.String" to type "System.Double".
#+ The specified original value (string) was "This string cannot be converted to Double".
#+ The node descriptor used was: NodeId="nsu=http://test.org/UA/Data/ ;i=10226".
#+ The client method called (or event/callback invoked) was 'WriteMultiple[3]'.
#Result 2: The status of the OPC-UA attribute data is not Good. The actual status is 'BadNodeIdUnknown'.
#+ During writing or method calls, readings may occur when value type is not specified.
#+ The node descriptor used was: NodeId="nsu=http://test.org/UA/Data/ ;s=UnknownNode".
#+ The client method called (or event/callback invoked) was 'WriteMultiple[3]'.
# This example shows how to write values into 3 nodes at once, test for success of each write and display the exception
# message in case of failure.

# The QuickOPC package is needed. Install it using "pip install opclabs_quickopc".
import opclabs_quickopc

# Import .NET namespaces.
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 values of nodes...')
writeResultArray = IEasyUAClientExtension.WriteMultipleValues(client, [
    UAWriteValueArguments(endpointDescriptor, UANodeDescriptor('nsu=http://test.org/UA/Data/ ;i=10221'), 23456),
    UAWriteValueArguments(endpointDescriptor, UANodeDescriptor('nsu=http://test.org/UA/Data/ ;i=10226'),
                          'This string cannot be converted to Double'),
    UAWriteValueArguments(endpointDescriptor, UANodeDescriptor('nsu=http://test.org/UA/Data/ ;s=UnknownNode'), 'ABC'),
    ])

for i, writeResult in enumerate(writeResultArray):
    if writeResult.Succeeded:
        print('writeResultArray[', i, ']: success', sep='')
    else:
        print('writeResultArray[', i, '] *** Failure: ', writeResult.Exception.GetBaseException().Message, sep='')

print()
print('Finished.')
' This example shows how to write values into 3 nodes at once, test for success of each write and display the exception 
' message in case of failure.

Imports System
Imports OpcLabs.BaseLib.OperationModel
Imports OpcLabs.EasyOpc.UA
Imports OpcLabs.EasyOpc.UA.OperationModel

Namespace _EasyUAClient
    Partial Friend Class WriteMultipleValues
        Public Shared Sub TestSuccess()

            ' 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()

            ' Modify value of a node
            Dim operationResultArray() As OperationResult = client.WriteMultipleValues(New UAWriteValueArguments() _
                { _
                    New UAWriteValueArguments(endpointDescriptor, "nsu=http://test.org/UA/Data/ ;i=10221", 23456), _
                    New UAWriteValueArguments(endpointDescriptor, "nsu=http://test.org/UA/Data/ ;i=10226", "This string cannot be converted to Double"), _
                    New UAWriteValueArguments(endpointDescriptor, "nsu=http://test.org/UA/Data/ ;s=UnknownNode", "ABC") _
                } _
             )

            For i As Integer = 0 To operationResultArray.Length - 1
                If operationResultArray(i).Succeeded Then
                    Console.WriteLine("Result {0}: success", i)
                Else
                    Console.WriteLine("Result {0}: {1}", i, operationResultArray(i).Exception.GetBaseException().Message)
                End If
            Next i
        End Sub
    End Class
End Namespace
// This example shows how to write values into 3 nodes at once, test for success of each write and display the exception 
// message in case of failure.

mle_outputtext.Text = ""

// Instantiate the client object
OLEObject client
client = CREATE OLEObject
client.ConnectToNewObject("OpcLabs.EasyOpc.UA.EasyUAClient")

// Prepare arguments. 

OLEObject writeValueArguments1
writeValueArguments1 = CREATE OLEObject
writeValueArguments1.ConnectToNewObject("OpcLabs.EasyOpc.UA.OperationModel.UAwriteValueArguments")
writeValueArguments1.EndpointDescriptor.UrlString = "http://opcua.demo-this.com:51211/UA/SampleServer"
writeValueArguments1.NodeDescriptor.NodeId.ExpandedText = "nsu=http://test.org/UA/Data/ ;i=10221"
writeValueArguments1.Value = 23456

OLEObject writeValueArguments2
writeValueArguments2 = CREATE OLEObject
writeValueArguments2.ConnectToNewObject("OpcLabs.EasyOpc.UA.OperationModel.UAwriteValueArguments")
writeValueArguments2.EndpointDescriptor.UrlString = "http://opcua.demo-this.com:51211/UA/SampleServer"
writeValueArguments2.NodeDescriptor.NodeId.ExpandedText = "nsu=http://test.org/UA/Data/ ;i=10226"
writeValueArguments2.Value = "This string cannot be converted to Double"

OLEObject writeValueArguments3
writeValueArguments3 = CREATE OLEObject
writeValueArguments3.ConnectToNewObject("OpcLabs.EasyOpc.UA.OperationModel.UAwriteValueArguments")
writeValueArguments3.EndpointDescriptor.UrlString = "http://opcua.demo-this.com:51211/UA/SampleServer"
writeValueArguments3.NodeDescriptor.NodeId.ExpandedText = "nsu=http://test.org/UA/Data/ ;s=UnknownNode"
writeValueArguments3.Value = "ABC"

OLEObject writeValueArgumentsList
writeValueArgumentsList = CREATE OLEObject
writeValueArgumentsList.ConnectToNewObject("OpcLabs.BaseLib.Collections.ElasticVector")
writeValueArgumentsList.Add(writeValueArguments1)
writeValueArgumentsList.Add(writeValueArguments2)
writeValueArgumentsList.Add(writeValueArguments3)

// Modify value of nodes

OLEObject operationResultList
operationResultList = client.WriteValueList(writeValueArgumentsList)

// Display results
Int i
FOR i = 0 TO operationResultList.Count - 1
    OLEObject operationResult
    operationResult = operationResultList.Item[i]
    IF operationResult.Succeeded THEN
        mle_outputtext.Text = mle_outputtext.Text + "Result " + String(i) + ": success" + "~r~n"
    ELSE
        mle_outputtext.Text = mle_outputtext.Text + "Result " + String(i) + ": " + operationResult.Exception.GetBaseException().Message + "~r~n"
    END IF    
NEXT

mle_outputtext.Text = mle_outputtext.Text + "~r~n" 
mle_outputtext.Text = mle_outputtext.Text + "Finished." + "~r~n" 
Requirements

Target Platforms: .NET Framework: Windows 10 (selected versions), Windows 11 (selected versions), Windows Server 2016, Windows Server 2022; .NET: Linux, macOS, Microsoft Windows

See Also