OPC Studio User's Guide and Reference
WriteMultipleItemValues Method (EasyDAClientCore)
Example 



OpcLabs.EasyOpcClassic Assembly > OpcLabs.EasyOpc.DataAccess Namespace > EasyDAClientCore Class : WriteMultipleItemValues Method
Array of argument objects for the operation.

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

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

Writes values into named items in an OPC server or OPC servers. Only the item values are written (qualities and timestamp are not written).
Syntax
'Declaration
 
Public Function WriteMultipleItemValues( _
   ByVal argumentsArray() As DAItemValueArguments _
) As OperationResult()
'Usage
 
Dim instance As EasyDAClientCore
Dim argumentsArray() As DAItemValueArguments
Dim value() As OperationResult
 
value = instance.WriteMultipleItemValues(argumentsArray)
public OperationResult[] WriteMultipleItemValues( 
   DAItemValueArguments[] argumentsArray
)

Parameters

argumentsArray
Array of argument objects for the operation.

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

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

Return Value

The function returns an array of OpcLabs.BaseLib.OperationModel.OperationResult objects. The indices of elements in the output array are the same as those in the input arrays.

This method never returns null (Nothing in Visual Basic).

The individual elements of the returned value are never null (Nothing in Visual Basic).

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.BaseLib.OperationModel.OperationResult element.

The server(s) can be local or can be remotely accessed via DCOM.

Optionally, a specific data type can be requested, or an access path can be specified (OPC DA 1.0 only).

Example
// Shows how to write into multiple OPC items using a single method call, and read multiple item values back.
//
// 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 System.Diagnostics;
using OpcLabs.BaseLib.OperationModel;
using OpcLabs.EasyOpc.DataAccess;
using OpcLabs.EasyOpc.DataAccess.OperationModel;

namespace DocExamples.DataAccess._EasyDAClient
{
    partial class WriteMultipleItemValues
    {
        public static void Main1()
        {
            // Instantiate the client object.
            var client = new EasyDAClient();

            Console.WriteLine("Writing multiple item values...");
            OperationResult[] resultArray = client.WriteMultipleItemValues(
                new[] { 
                    new DAItemValueArguments("", "OPCLabs.KitServer.2", "Simulation.Register_I4", 12345),
                    new DAItemValueArguments("", "OPCLabs.KitServer.2", "Simulation.Register_BOOL", true),
                    new DAItemValueArguments("", "OPCLabs.KitServer.2", "Simulation.Register_R4", 234.56)
                });
            
            for (int i = 0; i < resultArray.Length; i++)
            {
                Debug.Assert(resultArray[i] != null);
                if (resultArray[i].Succeeded)
                    Console.WriteLine($"Results[{i}]: success");
                else
                {
                    Debug.Assert(!(resultArray[i].Exception is null));
                    Console.WriteLine($"Results[{i}] *** Failure: {resultArray[i].ErrorMessageBrief}");
                }
            }

            Console.WriteLine();
            Console.WriteLine("Reading multiple item values...");
            ValueResult[] valueResultArray = client.ReadMultipleItemValues("OPCLabs.KitServer.2",
                new DAItemDescriptor[] { 
                        "Simulation.Register_I4", 
                        "Simulation.Register_BOOL", 
                        "Simulation.Register_R4" });

            for (int i = 0; i < valueResultArray.Length; i++)
            {
                Debug.Assert(valueResultArray[i] != null);
                Console.WriteLine($"valueResultArray[{i}]: {valueResultArray[i]}");
            }


            // Example output:
            //
            //Writing multiple item values...
            //Results[0]: success
            //Results[1]: success
            //Results[2]: success
            //
            //Reading multiple item values...
            //valueResultArray[0]: Success; 12345 {System.Int32}
            //valueResultArray[1]: Success; True {System.Boolean}
            //valueResultArray[2]: Success; 234.56 {System.Single}
        }
    }
}
# Shows how to write into multiple OPC items using a single method call, and read multiple item values back.
#
# 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.DataAccess
using namespace OpcLabs.EasyOpc.DataAccess.OperationModel

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

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

Write-Host "Writing multiple item values..."
$resultArray = $client.WriteMultipleItemValues(@(
    (New-Object DAItemValueArguments("", "OPCLabs.KitServer.2", "Simulation.Register_I4", 12345)),
    (New-Object DAItemValueArguments("", "OPCLabs.KitServer.2", "Simulation.Register_BOOL", $true)),
    (New-Object DAItemValueArguments("", "OPCLabs.KitServer.2", "Simulation.Register_R4", 234.56))
    ))

for ($i = 0; $i -lt $resultArray.Length; $i++) {
    $result = $resultArray[$i]
    if ($result.Succeeded) {
        Write-Host "Result $($i): success"
    }
    else {
        Write-Host "Result $($i) *** Failure: $($result.ErrorMessageBrief)"
    }
}

Write-Host 
Write-Host "Reading multiple item values..."
$valueResultArray = [IEasyDAClientExtension]::ReadMultipleItemValues($client, 
    "OPCLabs.KitServer.2", @(
        (New-Object DAItemDescriptor("Simulation.Register_I4")),
        (New-Object DAItemDescriptor("Simulation.Register_BOOL")),
        (New-Object DAItemDescriptor("Simulation.Register_R4"))
        ))

for ($i = 0; $i -lt $valueResultArray.Length; $i++) {
    $valueResult = $valueResultArray[$i]
    Write-Host "valueResultArray[$($i)]: $($valueResult)"
}


# Example output:
#
#Writing multiple item values...
#Result 0: success
#Result 1: success
#Result 2: success
#
#Reading multiple item values...
#valueResultArray[0]: Success; 12345 {System.Int32}
#valueResultArray[1]: Success; True {System.Boolean}
#valueResultArray[2]: Success; 234.56 {System.Single}
' This example shows how to write values into multiple items.
'
' 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.BaseLib.OperationModel
Imports OpcLabs.EasyOpc.DataAccess
Imports OpcLabs.EasyOpc.DataAccess.OperationModel

Namespace DataAccess._EasyDAClient
    Partial Friend Class WriteMultipleItemValues
        Public Shared Sub Main1()
            Dim client = New EasyDAClient()

            Dim argumentsArray = New DAItemValueArguments() { _
                New DAItemValueArguments("", "OPCLabs.KitServer.2", "Simulation.Register_I4", 12345), _
                New DAItemValueArguments("", "OPCLabs.KitServer.2", "Simulation.Register_BOOL", True), _
                New DAItemValueArguments("", "OPCLabs.KitServer.2", "Simulation.Register_R4", 234.56) _
            }

            Dim resultArray As OperationResult() = client.WriteMultipleItemValues(argumentsArray)

            For i = 0 To resultArray.Length - 1
                Debug.Assert(resultArray(i) IsNot Nothing)

                If resultArray(i).Succeeded Then
                    Console.WriteLine("Results[{0}]: success", i)
                Else
                    Console.WriteLine("Results[{0}] *** Failure: {1}", i, resultArray(i).ErrorMessageBrief)
                End If
            Next i

            Console.WriteLine("Reading multiple item values...")
            Dim valueResultArray() As ValueResult = client.ReadMultipleItemValues("OPCLabs.KitServer.2", _
                New DAItemDescriptor() { _
                    "Simulation.Register_I4",
                    "Simulation.Register_BOOL",
                    "Simulation.Register_R4"})

            For i = 0 To valueResultArray.Length - 1
                Debug.Assert(valueResultArray(i) IsNot Nothing)
                Console.WriteLine("valueResultArray[{0}]: {1}", i, valueResultArray(i))
            Next i

        End Sub
    End Class
End Namespace
// This example shows how to write values into 3 items at once.
//
// Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .
// OPC client and subscriber examples in PHP on GitHub: https://github.com/OPCLabs/Examples-QuickOPC-PHP .
// 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.

$ItemValueArguments1 = new COM("OpcLabs.EasyOpc.DataAccess.OperationModel.DAItemValueArguments");
$ItemValueArguments1->ServerDescriptor->ServerClass = "OPCLabs.KitServer.2";
$ItemValueArguments1->ItemDescriptor->ItemID = "Simulation.Register_I4";
$ItemValueArguments1->Value = 23456;

$ItemValueArguments2 = new COM("OpcLabs.EasyOpc.DataAccess.OperationModel.DAItemValueArguments");
$ItemValueArguments2->ServerDescriptor->ServerClass = "OPCLabs.KitServer.2";
$ItemValueArguments2->ItemDescriptor->ItemID = "Simulation.Register_R8";
$ItemValueArguments2->Value = 2.34567890;

$ItemValueArguments3 = new COM("OpcLabs.EasyOpc.DataAccess.OperationModel.DAItemValueArguments");
$ItemValueArguments3->ServerDescriptor->ServerClass = "OPCLabs.KitServer.2";
$ItemValueArguments3->ItemDescriptor->ItemID = "Simulation.Register_BSTR";
$ItemValueArguments3->Value = "ABC";

$arguments[0] = $ItemValueArguments1;
$arguments[1] = $ItemValueArguments2;
$arguments[2] = $ItemValueArguments3;

$Client = new COM("OpcLabs.EasyOpc.DataAccess.EasyDAClient");
$results = $Client->WriteMultipleItemValues($arguments);

for ($i = 0; $i < count($results); $i++)
{
    $OperationResult = $results[$i];
    if ($OperationResult->Succeeded)
        printf("Result %d: success\n", $i);
    else
        printf("Result  s\n", $i, $OperationResult->ErrorMessageBrief);
}
# This example shows how to write values, timestamps and qualities into 3 items at once.
#
# 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 import *
from OpcLabs.EasyOpc.DataAccess import *
from OpcLabs.EasyOpc.DataAccess.OperationModel import *
from OpcLabs.EasyOpc.OperationModel import *


# Instantiate the client object.
client = EasyDAClient()

print('Writing multiple items...')
operationResultArray = client.WriteMultipleItems([
    DAItemVtqArguments(ServerDescriptor('OPCLabs.KitServer.2'), DAItemDescriptor('Simulation.Register_I4'),
                       DAVtq(23456, DateTime.UtcNow, DAQuality(DAQualities.GoodNonspecific))),
    DAItemVtqArguments(ServerDescriptor('OPCLabs.KitServer.2'), DAItemDescriptor('Simulation.Register_R8'),
                       DAVtq(2.34567890, DateTime.UtcNow, DAQuality(DAQualities.GoodNonspecific))),
    DAItemVtqArguments(ServerDescriptor('OPCLabs.KitServer.2'), DAItemDescriptor('Simulation.Register_BSTR'),
                       DAVtq('ABC', DateTime.UtcNow, DAQuality(DAQualities.GoodNonspecific))),
    ])

for i, operationResult in enumerate(operationResultArray):
    assert operationResult is not None
    if operationResult.Succeeded:
        print('operationResultArray[', i, ']: success', sep='')
    else:
        assert operationResult.Exception is not None
        print('operationResultArray[', i, '] *** Failure: ', operationResult.ErrorMessageBrief, sep='')

print('Finished.')
// Shows how to write into multiple OPC items using a single method call, specifying their requested data types.
//
// 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 System.Diagnostics;
using OpcLabs.BaseLib.ComInterop;
using OpcLabs.BaseLib.OperationModel;
using OpcLabs.EasyOpc.DataAccess;
using OpcLabs.EasyOpc.DataAccess.OperationModel;

namespace DocExamples.DataAccess._EasyDAClient
{
    partial class WriteMultipleItemValues
    {
        public static void RequestedDataType()
        {
            // Instantiate the client object.
            var client = new EasyDAClient();

            Console.WriteLine("Writing multiple item values...");
            OperationResult[] resultArray = client.WriteMultipleItemValues(new[] { 
                    new DAItemValueArguments("", "OPCLabs.KitServer.2", "Simulation.Register_I2", 12345) 
                        { ItemDescriptor = { RequestedDataType = VarTypes.I2}}, // <-- the requested data type
                    new DAItemValueArguments("", "OPCLabs.KitServer.2", "Simulation.Register_R4", 234.56)
                        { ItemDescriptor = { RequestedDataType = VarTypes.R4}}  // <-- the requested data type 
                });


            for (int i = 0; i < resultArray.Length; i++)
            {
                Debug.Assert(resultArray[i] != null);
                if (resultArray[i].Succeeded)
                    Console.WriteLine("Result {0}: success", i);
                else
                {
                    Debug.Assert(!(resultArray[i].Exception is null));
                    Console.WriteLine("Result {0} *** Failure: {1}", i, resultArray[i].ErrorMessageBrief);
                }
            }

            Console.WriteLine("Reading multiple item values...");
            ValueResult[] valueResultArray = client.ReadMultipleItemValues("OPCLabs.KitServer.2",
                new DAItemDescriptor[] { "Simulation.Register_I2", "Simulation.Register_R4" });

            for (int i = 0; i < valueResultArray.Length; i++)
            {
                Debug.Assert(valueResultArray[i] != null);
                Console.WriteLine("valueResultArray[{0}]: {1}", i, valueResultArray[i]);
            }
        }
    }
}
' Shows how to write into multiple OPC items using a single method call, specifying their requested data types.
'
' 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.BaseLib.ComInterop
Imports OpcLabs.EasyOpc.DataAccess
Imports OpcLabs.EasyOpc.DataAccess.OperationModel

Namespace DataAccess._EasyDAClient
    Partial Friend Class WriteMultipleItemValues
        Public Shared Sub RequestedDataType()
            Dim client = New EasyDAClient()

            Console.WriteLine("Writing multiple item values...")
            Dim resultArray = client.WriteMultipleItemValues(New DAItemValueArguments() { _
                New DAItemValueArguments("", "OPCLabs.KitServer.2", "Simulation.Register_I2", 12345) With _
                {.ItemDescriptor = New DAItemDescriptor() With {.RequestedDataType = VarTypes.I2}}, _
                New DAItemValueArguments("", "OPCLabs.KitServer.2", "Simulation.Register_R4", 234.56) With _
                {.ItemDescriptor = New DAItemDescriptor() With {.RequestedDataType = VarTypes.R4}} _
            })

            For i = 0 To resultArray.Length - 1
                Debug.Assert(resultArray(i) IsNot Nothing)
                If resultArray(i).Succeeded Then
                    Console.WriteLine("Result {0}: success", i)
                Else
                    Debug.Assert(resultArray(i).Exception IsNot Nothing)
                    Console.WriteLine("Result {0} *** Failure: {1}", i, resultArray(i).ErrorMessageBrief)
                End If
            Next i

            Console.WriteLine("Reading multiple item values...")
            Dim valueResultArray = client.ReadMultipleItemValues("OPCLabs.KitServer.2",
                    New DAItemDescriptor() {"Simulation.Register_I2", "Simulation.Register_R4"})

            For i = 0 To valueResultArray.Length - 1
                Debug.Assert(valueResultArray(i) IsNot Nothing)
                Console.WriteLine("valueResultArray[{0}]: {1}", i, valueResultArray(i))
            Next i
        End Sub
    End Class
End Namespace
# Shows how to write into multiple OPC items using a single method call, specifying their requested data types.
#
# 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 OpcLabs.BaseLib.ComInterop import *
from OpcLabs.EasyOpc import *
from OpcLabs.EasyOpc.DataAccess import *
from OpcLabs.EasyOpc.DataAccess.OperationModel import *
from OpcLabs.EasyOpc.OperationModel import *


# Instantiate the client object.
client = EasyDAClient()

print('Writing multiple item values...')
arguments1 = DAItemValueArguments(ServerDescriptor('OPCLabs.KitServer.2'),
                                  DAItemDescriptor('Simulation.Register_I2'),
                                  12345)
arguments1.ItemDescriptor.RequestedDataType = VarType(VarTypes.I2)  # <-- the requested data type
arguments2 = DAItemValueArguments(ServerDescriptor('OPCLabs.KitServer.2'),
                                  DAItemDescriptor('Simulation.Register_R4'),
                                  234.56)
arguments2.ItemDescriptor.RequestedDataType = VarType(VarTypes.R4)  # <-- the requested data type
operationResultArray = client.WriteMultipleItemValues([arguments1, arguments2])

for i, operationResult in enumerate(operationResultArray):
    assert operationResult is not None
    if operationResult.Succeeded:
        print('operationResultArray[', i, ']: success', sep='')
    else:
        assert operationResult.Exception is not None
        print('operationResultArray[', i, '] *** Failure: ', operationResult.ErrorMessageBrief, sep='')

print('Reading multiple item values...')
try:
    valueResultArray = IEasyDAClientExtension.ReadMultipleItemValues(client, ServerDescriptor('OPCLabs.KitServer.2'), [
        DAItemDescriptor('Simulation.Register_I2'),
        DAItemDescriptor('Simulation.Register_R4'),
    ])
except OpcException as opcException:
    print('*** Failure: ' + opcException.GetBaseException().Message, sep='')
    exit()

for i, valueResult in enumerate(valueResultArray):
    assert valueResult is not None
    if valueResult.Succeeded:
        print('valueResultArray[', i, '].Value: ', valueResult.Value, sep='')
    else:
        assert valueResult.Exception is not None
        print('valueResultArray[', i, '] *** Failure: ', valueResult.ErrorMessageBrief, sep='')

print('Finished.')
// This example measures the time needed to write 2000 item values all at once, and in 20 groups by 100 items.
// Note that the writes will currently all fail, as we do not have the appropriate writeable items available.
//
// 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 System.Diagnostics;
using System.Threading;
using OpcLabs.BaseLib.OperationModel;
using OpcLabs.EasyOpc.DataAccess.OperationModel;
using OpcLabs.EasyOpc.DataAccess;

namespace DocExamples.DataAccess._EasyDAClient
{
    partial class WriteMultipleItemValues
    {
        const int NumberOfGroups = 100;
        const int ItemsInGroup = 20;
        private const int TotalItems = NumberOfGroups * ItemsInGroup;

        // Main method
        public static void TimeMeasurements()
        {
            // Make the measurements 10 times; note that first time the times might be longer.
            for (int i = 1; i <= 10; i++)
            {
                // Pause - we do not want the component to use the values it has in memory
                Thread.Sleep(2 * 1000);

                // Write all item values at once, and measure the time
                var stopwatch1 = new Stopwatch();
                stopwatch1.Start();
                WriteAllAtOnce();
                stopwatch1.Stop();
                Console.WriteLine("WriteAllAtOnce has taken (milliseconds): {0}", stopwatch1.ElapsedMilliseconds);

                // Pause - we do not want the component to use the values it has in memory
                Thread.Sleep(2 * 1000);

                // Write item values in groups, and measure the time
                var stopwatch2 = new Stopwatch();
                stopwatch2.Start();
                WriteInGroups();
                stopwatch2.Stop();
                Console.WriteLine("WriteInGroups has taken (milliseconds): {0}", stopwatch2.ElapsedMilliseconds);
            }
        }

        // Write all item values at once
        private static void WriteAllAtOnce()
        {
            // Instantiate the client object.
            var client = new EasyDAClient();

            // Create an array of arguments for all items
            var arguments = new DAItemValueArguments[TotalItems];
            int index = 0;
            for (int iLoop = 0; iLoop < NumberOfGroups; iLoop++)
                for (int iItem = 0; iItem < ItemsInGroup; iItem++)
                    arguments[index++] = new DAItemValueArguments(
                        "OPCLabs.KitServer.2",
                        String.Format("Simulation.Incrementing.Copy_{0}.Phase_{1}", iLoop + 1, iItem + 1),
                        0);

            // Perform the OPC write
            OperationResult[] operationResults = client.WriteMultipleItemValues(arguments);

            // Count successful results
            int successCount = 0;
            for (int iItem = 0; iItem < TotalItems; iItem++)
            {
                Debug.Assert(operationResults[iItem] != null);
                if (operationResults[iItem].Succeeded)
                    successCount++;
            }

            if (successCount != TotalItems)
                Console.WriteLine("Warning: There were some failures, success count is {0}", successCount);
        }

        // Write item values in groups
        private static void WriteInGroups()
        {
            var client = new EasyDAClient();

            int successCount = 0;
            for (int iLoop = 0; iLoop < NumberOfGroups; iLoop++)
            {
                // Create an array of item arguments for items in one group
                var arguments = new DAItemValueArguments[ItemsInGroup];
                for (int iItem = 0; iItem < ItemsInGroup; iItem++)
                    arguments[iItem] = new DAItemValueArguments(
                        "OPCLabs.KitServer.2",
                        String.Format("Simulation.Incrementing.Copy_{0}.Phase_{1}", iLoop + 1, iItem + 1),
                        0);

                // Perform the OPC write
                OperationResult[] operationResults = client.WriteMultipleItemValues(arguments);

                // Count successful results (totalling to previous value)
                for (int iItem = 0; iItem < ItemsInGroup; iItem++)
                {
                    Debug.Assert(operationResults[iItem] != null);
                    if (operationResults[iItem].Succeeded) successCount++;
                }
            }

            if (successCount != TotalItems)
                Console.WriteLine("Warning: There were some failures, success count is {0}", successCount);
        }
    }
}
' This example measures the time needed to write 2000 item values all at once, and in 20 groups by 100 items.
' Note that the writes will currently all fail, as we do not have the appropriate writeable items available.
'
' 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 System.Threading
Imports OpcLabs.BaseLib.OperationModel
Imports OpcLabs.EasyOpc.DataAccess
Imports OpcLabs.EasyOpc.DataAccess.OperationModel

Namespace DataAccess._EasyDAClient
    Partial Friend Class WriteMultipleItemValues
        Private Const NumberOfGroups As Integer = 100
        Private Const ItemsInGroup As Integer = 20
        Private Const TotalItems As Integer = NumberOfGroups * ItemsInGroup

        ' Main method
        Public Shared Sub TimeMeasurements()
            ' Make the measurements 10 times; note that first time the times might be longer.
            For i As Integer = 1 To 10
                ' Pause - we do not want the component to use the values it has in memory
                Thread.Sleep(2 * 1000)

                '  Write all item values at once, and measure the time
                Dim stopwatch1 = New Stopwatch()
                stopwatch1.Start()
                WriteAllAtOnce()
                stopwatch1.Stop()
                Console.WriteLine("WriteAllAtOnce has taken (milliseconds): {0}", stopwatch1.ElapsedMilliseconds)

                ' Pause - we do not want the component to use the values it has in memory
                Thread.Sleep(2 * 1000)

                ' Write item values in groups, and measure the time
                Dim stopwatch2 = New Stopwatch()
                stopwatch2.Start()
                WriteInGroups()
                stopwatch2.Stop()
                Console.WriteLine("WriteInGroups has taken (milliseconds): {0}", stopwatch2.ElapsedMilliseconds)
            Next i
        End Sub

        '  Write all item values at once
        Private Shared Sub WriteAllAtOnce()
            Dim client = New EasyDAClient()

            ' Create an array of arguments for all items
            Dim arguments = New DAItemValueArguments(TotalItems - 1) {}
            Dim index As Integer = 0
            For iLoop As Integer = 0 To NumberOfGroups - 1
                For iItem As Integer = 0 To ItemsInGroup - 1
                    arguments(index) = New DAItemValueArguments(
                        "OPCLabs.KitServer.2",
                            String.Format("Simulation.Incrementing.Copy_{0}.Phase_{1}", iLoop + 1, iItem + 1),
                            0)
                    index += 1
                Next iItem
            Next iLoop

            ' Perform the OPC write
            Dim operationResults() As OperationResult = client.WriteMultipleItemValues(arguments)

            ' Count successful results
            Dim successCount As Integer = 0
            For iItem As Integer = 0 To TotalItems - 1
                Debug.Assert(operationResults(iItem) IsNot Nothing)
                If operationResults(iItem).Succeeded Then
                    successCount += 1
                End If
            Next iItem

            If successCount <> TotalItems Then
                Console.WriteLine("Warning: There were some failures, success count is {0}", successCount)
            End If
        End Sub

        ' Write item values in groups
        Private Shared Sub WriteInGroups()
            Dim client = New EasyDAClient()

            Dim successCount As Integer = 0
            For iLoop As Integer = 0 To NumberOfGroups - 1
                ' Create an array of item arguments for items in one group
                Dim arguments = New DAItemValueArguments(ItemsInGroup - 1) {}
                For iItem As Integer = 0 To ItemsInGroup - 1
                    arguments(iItem) = New DAItemValueArguments(
                            "OPCLabs.KitServer.2",
                            String.Format("Simulation.Incrementing.Copy_{0}.Phase_{1}", iLoop + 1, iItem + 1),
                            0)
                Next iItem

                ' Perform the OPC write
                Dim operationResults() As OperationResult = client.WriteMultipleItemValues(arguments)

                ' Count successful results (totalling to previous value)
                For iItem As Integer = 0 To ItemsInGroup - 1
                    Debug.Assert(operationResults(iItem) IsNot Nothing)
                    If operationResults(iItem).Succeeded Then
                        successCount += 1
                    End If
                Next iItem
            Next iLoop

            If successCount <> TotalItems Then
                Console.WriteLine("Warning: There were some failures, success count is {0}", successCount)
            End If
        End Sub
    End Class
End Namespace
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