QuickOPC User's Guide and Reference
Examples - OPC Data Access - Unsubscribe from multiple items

.NET

// This example shows how to unsubscribe from changes of multiple items.

using System;
using System.Threading;
using OpcLabs.EasyOpc.DataAccess;
using OpcLabs.EasyOpc.DataAccess.OperationModel;

namespace DocExamples.DataAccess._EasyDAClient
{
    class UnsubscribeMultipleItems
    {
        public static void Main1()
        {
            // Instantiate the client object.
            using (var client = new EasyDAClient())
            {
                client.ItemChanged += client_ItemChanged;

                Console.WriteLine("Subscribing...");
                int[] handleArray = client.SubscribeMultipleItems(
                    new[] {
                            new DAItemGroupArguments("", "OPCLabs.KitServer.2", "Simulation.Random", 1000, null), 
                            new DAItemGroupArguments("", "OPCLabs.KitServer.2", "Trends.Ramp (1 min)", 1000, null), 
                            new DAItemGroupArguments("", "OPCLabs.KitServer.2", "Trends.Sine (1 min)", 1000, null),  
                            new DAItemGroupArguments("", "OPCLabs.KitServer.2", "Simulation.Register_I4", 1000, null)
                        });

                for (int i = 0; i < handleArray.Length; i++)
                    Console.WriteLine($"handleArray({i}): {handleArray[i]}");

                Console.WriteLine("Processing item changed events for 10 seconds...");
                Thread.Sleep(10 * 1000);

                Console.WriteLine("Unsubscribing from two items...");
                client.UnsubscribeMultipleItems(new [] {handleArray[1], handleArray[2]});

                Console.WriteLine("Processing item changed events for 10 seconds...");
                Thread.Sleep(10 * 1000);

                Console.WriteLine("Unsubscribing from all remaining items...");
                client.UnsubscribeAllItems();

                Console.WriteLine("Waiting for 5 seconds...");
                Thread.Sleep(5 * 1000);
            }
        }

        // Item changed event handler
        static void client_ItemChanged(object sender, EasyDAItemChangedEventArgs e)
        {
            if (e.Succeeded)
                Console.WriteLine("{0}: {1}", e.Arguments.ItemDescriptor.ItemId, e.Vtq);
            else
                Console.WriteLine("{0} *** Failure: {1}", e.Arguments.ItemDescriptor.ItemId, e.ErrorMessageBrief);
        }


        // Example output:
        //
        //Subscribing...
        //handleArray(0): 12586002
        //handleArray(1) : 12586004
        //handleArray(2) : 12586005
        //handleArray(3) : 12586006
        //Processing item changed events for 10 seconds...
        //Simulation.Register_I4: 0 {System.Int32} @1601-01-01T00:00:00.000; GoodNonspecific(192)
        //Trends.Ramp(1 min): 0.585198730230331 {System.Double} @2020-04-10T15:50:35.111; GoodNonspecific(192)
        //Simulation.Random: 0.00125125888851588 {System.Double} @2020-04-10T15:50:35.111; GoodNonspecific(192)
        //Trends.Sine(1 min): -0.51011579179648 {System.Double} @2020-04-10T15:50:35.111; GoodNonspecific(192)
        //Trends.Ramp(1 min): 0.601875007152557 {System.Double} @2020-04-10T15:50:36.112; GoodNonspecific(192)
        //Simulation.Random: 0.56358531449324 {System.Double} @2020-04-10T15:50:36.112; GoodNonspecific(192)
        //Trends.Sine(1 min): -0.597275285519755 {System.Double} @2020-04-10T15:50:36.112; GoodNonspecific(192)
        //Trends.Ramp(1 min): 0.618548572063446 {System.Double} @2020-04-10T15:50:37.112; GoodNonspecific(192)
        //Simulation.Random: 0.193304239020966 {System.Double} @2020-04-10T15:50:37.112; GoodNonspecific(192)
        //Trends.Sine(1 min): -0.677870836926452 {System.Double} @2020-04-10T15:50:37.112; GoodNonspecific(192)
        //Trends.Ramp(1 min): 0.635226935148239 {System.Double} @2020-04-10T15:50:38.113; GoodNonspecific(192)
        //Simulation.Random: 0.808740501113926 {System.Double} @2020-04-10T15:50:38.113; GoodNonspecific(192)
        //Trends.Sine(1 min): -0.751053255223256 {System.Double} @2020-04-10T15:50:38.113; GoodNonspecific(192)
        //Trends.Ramp(1 min): 0.65190464258194 {System.Double} @2020-04-10T15:50:39.114; GoodNonspecific(192)
        //Simulation.Random: 0.58500930814539 {System.Double} @2020-04-10T15:50:39.114; GoodNonspecific(192)
        //Trends.Sine(1 min): -0.815993052494079 {System.Double} @2020-04-10T15:50:39.114; GoodNonspecific(192)
        //Trends.Ramp(1 min): 0.668579548597336 {System.Double} @2020-04-10T15:50:40.114; GoodNonspecific(192)
        //Simulation.Random: 0.47987304300058 {System.Double} @2020-04-10T15:50:40.114; GoodNonspecific(192)
        //Trends.Sine(1 min): -0.87197220432209 {System.Double} @2020-04-10T15:50:40.114; GoodNonspecific(192)
        //Trends.Ramp(1 min): 0.68526017665863 {System.Double} @2020-04-10T15:50:41.115; GoodNonspecific(192)
        //Simulation.Random: 0.350291451765496 {System.Double} @2020-04-10T15:50:41.115; GoodNonspecific(192)
        //Trends.Sine(1 min): -0.918402631917152 {System.Double} @2020-04-10T15:50:41.115; GoodNonspecific(192)
        //Trends.Ramp(1 min): 0.701931446790695 {System.Double} @2020-04-10T15:50:42.115; GoodNonspecific(192)
        //Simulation.Random: 0.895962401196326 {System.Double} @2020-04-10T15:50:42.115; GoodNonspecific(192)
        //Trends.Sine(1 min): -0.954736510704127 {System.Double} @2020-04-10T15:50:42.115; GoodNonspecific(192)
        //Trends.Ramp(1 min): 0.718607157468796 {System.Double} @2020-04-10T15:50:43.116; GoodNonspecific(192)
        //Simulation.Random: 0.822840052491836 {System.Double} @2020-04-10T15:50:43.116; GoodNonspecific(192)
        //Trends.Sine(1 min): -0.98060979065431 {System.Double} @2020-04-10T15:50:43.116; GoodNonspecific(192)
        //Trends.Ramp(1 min): 0.735284030437469 {System.Double} @2020-04-10T15:50:44.117; GoodNonspecific(192)
        //Simulation.Random: 0.746604815820795 {System.Double} @2020-04-10T15:50:44.117; GoodNonspecific(192)
        //Trends.Sine(1 min): -0.995728326344284 {System.Double} @2020-04-10T15:50:44.117; GoodNonspecific(192)
        //Unsubscribing from two items...
        //Processing item changed events for 10 seconds...
        //Simulation.Random: 0.174108096560564 { System.Double} @2020-04-10T15:50:45.117; GoodNonspecific(192)
        //Simulation.Random: 0.858943449201941 {System.Double} @2020-04-10T15:50:46.118; GoodNonspecific(192)
        //Simulation.Random: 0.710501419110691 {System.Double} @2020-04-10T15:50:47.118; GoodNonspecific(192)
        //Simulation.Random: 0.513534958952605 {System.Double} @2020-04-10T15:50:48.120; GoodNonspecific(192)
        //Simulation.Random: 0.303994872890408 {System.Double} @2020-04-10T15:50:49.120; GoodNonspecific(192)
        //Simulation.Random: 0.0149845881527146 {System.Double} @2020-04-10T15:50:50.121; GoodNonspecific(192)
        //Simulation.Random: 0.0914029358806116 {System.Double} @2020-04-10T15:50:51.122; GoodNonspecific(192)
        //Simulation.Random: 0.364452040162358 {System.Double} @2020-04-10T15:50:52.124; GoodNonspecific(192)
        //Simulation.Random: 0.147312845240638 {System.Double} @2020-04-10T15:50:53.125; GoodNonspecific(192)
        //Unsubscribing from all remaining items...
        //Waiting for 5 seconds...
    }
}

# This example shows how to unsubscribe from changes of multiple items.

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

# Import .NET namespaces.
from System.Collections.Generic import *
from OpcLabs.EasyOpc.DataAccess import *
from OpcLabs.EasyOpc.DataAccess.OperationModel import *


# Item changed event handler.
def itemChanged(sender, e):
    if e.Succeeded:
        print(e.Arguments.ItemDescriptor.ItemId, ': ', e.Vtq, sep='')
    else:
        print(e.Arguments.ItemDescriptor.ItemId, ' *** Failure: ', e.ErrorMessageBrief, sep='')


# Instantiate the client object.
client = EasyDAClient()

client.ItemChanged += itemChanged

print('Subscribing item changes...')
handleArray = client.SubscribeMultipleItems([
    EasyDAItemSubscriptionArguments('', 'OPCLabs.KitServer.2', 'Simulation.Random', 1000, None),
    EasyDAItemSubscriptionArguments('', 'OPCLabs.KitServer.2', 'Trends.Ramp (1 min)', 1000, None),
    EasyDAItemSubscriptionArguments('', 'OPCLabs.KitServer.2', 'Trends.Sine (1 min)', 1000, None),
    EasyDAItemSubscriptionArguments('', 'OPCLabs.KitServer.2', 'Simulation.Register_I4', 1000, None),
    ])

for i in range(len(handleArray)):
    print('handleArray[', i, ']: ', handleArray[i], sep='')

print('Processing item change notifications for 10 seconds...')
time.sleep(10)

print('Unsubscribing from two items...')
handleList = List[int]()
handleList.Add(handleArray[1])
handleList.Add(handleArray[2])
client.UnsubscribeMultipleItems(handleList)

print('Processing item change notifications for 10 seconds...')
time.sleep(10)

print('Unsubscribing from all remaining items...')
client.UnsubscribeAllItems()

print('Waiting for 5 seconds...')
time.sleep(5)

client.ItemChanged -= itemChanged

print('Finished.')

COM

Rem This example shows how to unsubscribe from changes of multiple items.

Option Explicit

Dim ItemSubscriptionArguments1: Set ItemSubscriptionArguments1 = CreateObject("OpcLabs.EasyOpc.DataAccess.OperationModel.EasyDAItemSubscriptionArguments")
ItemSubscriptionArguments1.ServerDescriptor.ServerClass = "OPCLabs.KitServer.2"
ItemSubscriptionArguments1.ItemDescriptor.ItemID = "Simulation.Random"
ItemSubscriptionArguments1.GroupParameters.RequestedUpdateRate = 1000

Dim ItemSubscriptionArguments2: Set ItemSubscriptionArguments2 = CreateObject("OpcLabs.EasyOpc.DataAccess.OperationModel.EasyDAItemSubscriptionArguments")
ItemSubscriptionArguments2.ServerDescriptor.ServerClass = "OPCLabs.KitServer.2"
ItemSubscriptionArguments2.ItemDescriptor.ItemID = "Trends.Ramp (1 min)"
ItemSubscriptionArguments2.GroupParameters.RequestedUpdateRate = 1000

Dim ItemSubscriptionArguments3: Set ItemSubscriptionArguments3 = CreateObject("OpcLabs.EasyOpc.DataAccess.OperationModel.EasyDAItemSubscriptionArguments")
ItemSubscriptionArguments3.ServerDescriptor.ServerClass = "OPCLabs.KitServer.2"
ItemSubscriptionArguments3.ItemDescriptor.ItemID = "Trends.Sine (1 min)"
ItemSubscriptionArguments3.GroupParameters.RequestedUpdateRate = 1000

Dim ItemSubscriptionArguments4: Set ItemSubscriptionArguments4 = CreateObject("OpcLabs.EasyOpc.DataAccess.OperationModel.EasyDAItemSubscriptionArguments")
ItemSubscriptionArguments4.ServerDescriptor.ServerClass = "OPCLabs.KitServer.2"
ItemSubscriptionArguments4.ItemDescriptor.ItemID = "Simulation.Register_I4"
ItemSubscriptionArguments4.GroupParameters.RequestedUpdateRate = 1000

Dim arguments(3)
Set arguments(0) = ItemSubscriptionArguments1
Set arguments(1) = ItemSubscriptionArguments2
Set arguments(2) = ItemSubscriptionArguments3
Set arguments(3) = ItemSubscriptionArguments4

Dim Client: Set Client = CreateObject("OpcLabs.EasyOpc.DataAccess.EasyDAClient")
WScript.ConnectObject Client, "Client_"

WScript.Echo "Subscribing..."
Dim handleArray: handleArray = Client.SubscribeMultipleItems(arguments)

Dim i: For i = LBound(handleArray) To UBound(handleArray)
    WScript.Echo "handleArray(" & i & "): " & handleArray(i)
Next

WScript.Echo "Processing item changed events for 10 seconds..."
WScript.Sleep 10 * 1000

WScript.Echo "Unsubscribing from two items..."
Dim handles1(1)
handles1(0) = handleArray(1)
handles1(1) = handleArray(2)
Client.UnsubscribeMultipleItems handles1

WScript.Echo "Processing item changed events for 10 seconds..."
WScript.Sleep 10 * 1000

WScript.Echo "Unsubscribing from all remaining items..."
Client.UnsubscribeAllItems

WScript.Echo "Waiting for 5 seconds..."
WScript.Sleep 5 * 1000



Sub Client_ItemChanged(Sender, e)
    If Not (e.Succeeded) Then
        WScript.Echo "*** Failure: " & e.ErrorMessageBrief
        Exit Sub
    End If

    WScript.Echo e.Arguments.ItemDescriptor.ItemId & ": " & e.Vtq
End Sub

// This example shows how to unsubscribe from changes of multiple items.

class DEasyDAClientEvents {
    function ItemChanged($varSender, $varE)
    {
        if ($varE->Succeeded)
        {
            printf("s: s\n", $varE->Arguments->ItemDescriptor->ItemId, $varE->Vtq->ToString());
        }
        else
        {
            printf("*** Failure: %s\n", $varE->ErrorMessageBrief);
        }
    }
}

$ItemSubscriptionArguments1 = new COM("OpcLabs.EasyOpc.DataAccess.OperationModel.EasyDAItemSubscriptionArguments");
$ItemSubscriptionArguments1->ServerDescriptor->ServerClass = "OPCLabs.KitServer.2";
$ItemSubscriptionArguments1->ItemDescriptor->ItemID = "Simulation.Random";
$ItemSubscriptionArguments1->GroupParameters->RequestedUpdateRate = 1000;

$ItemSubscriptionArguments2 = new COM("OpcLabs.EasyOpc.DataAccess.OperationModel.EasyDAItemSubscriptionArguments");
$ItemSubscriptionArguments2->ServerDescriptor->ServerClass = "OPCLabs.KitServer.2";
$ItemSubscriptionArguments2->ItemDescriptor->ItemID = "Trends.Ramp (1 min)";
$ItemSubscriptionArguments2->GroupParameters->RequestedUpdateRate = 1000;

$ItemSubscriptionArguments3 = new COM("OpcLabs.EasyOpc.DataAccess.OperationModel.EasyDAItemSubscriptionArguments");
$ItemSubscriptionArguments3->ServerDescriptor->ServerClass = "OPCLabs.KitServer.2";
$ItemSubscriptionArguments3->ItemDescriptor->ItemID = "Trends.Sine (1 min)";
$ItemSubscriptionArguments3->GroupParameters->RequestedUpdateRate = 1000;

$ItemSubscriptionArguments4 = new COM("OpcLabs.EasyOpc.DataAccess.OperationModel.EasyDAItemSubscriptionArguments");
$ItemSubscriptionArguments4->ServerDescriptor->ServerClass = "OPCLabs.KitServer.2";
$ItemSubscriptionArguments4->ItemDescriptor->ItemID = "Simulation.Register_I4";
$ItemSubscriptionArguments4->GroupParameters->RequestedUpdateRate = 1000;

$arguments[0] = $ItemSubscriptionArguments1;
$arguments[1] = $ItemSubscriptionArguments2;
$arguments[2] = $ItemSubscriptionArguments3;
$arguments[3] = $ItemSubscriptionArguments4;

$Client = new COM("OpcLabs.EasyOpc.DataAccess.EasyDAClient");
$Events = new DEasyDAClientEvents();
com_event_sink($Client, $Events, "DEasyDAClientEvents");

print "Subscribing...\n";
$handleArray = $Client->SubscribeMultipleItems($arguments);

for ($i = 0; $i < count($handleArray); $i++)
{
    printf("handleArray[d]s\n", $i, $handleArray[$i]);
}

print "Processing item changed events for 10 seconds...\n";
$startTime = time(); do { com_message_pump(1000); } while (time() < $startTime + 10);

print "Unsubscribing from two items...\n";
$handles1[0] = $handleArray[1];
$handles1[1] = $handleArray[2];
$Client->UnsubscribeMultipleItems($handles1);

print "Processing item changed events for 10 seconds...\n";
$startTime = time(); do { com_message_pump(1000); } while (time() < $startTime + 10);

print "Unsubscribing from all remaining items...\n";
$Client->UnsubscribeAllItems;

print "Waiting for 5 seconds...\n";
$startTime = time(); do { com_message_pump(1000); } while (time() < $startTime + 5);

 

See Also
Examples - OPC Data Access - Unsubscribe from all items
Examples - OPC Data Access - Unsubscribe from a single item

Conceptual

Unsubscribing (OPC Data)

Examples - OPC Unified Architecture

Examples - OPC Unified Architecture - Unsubscribe from multiple monitored items

 

 

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