Examples - OPC Data Access - Identify subscriptions by an integer state

// This example shows how subscribe to changes of multiple items and display each change, identifying the different
// subscriptions by an integer.
//
// Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .

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

namespace DocExamples.DataAccess._EasyDAClient
{
    partial class SubscribeMultipleItems
    {
        public static void StateAsInteger()
        {
            // Instantiate the client object.
            using (var client = new EasyDAClient())
            {
                // Hook events
                client.ItemChanged += client_StateAsInteger_ItemChanged;

                Console.WriteLine("Subscribing...");
                int[] handleArray = client.SubscribeMultipleItems(new[]
                {
                    new DAItemGroupArguments("", "OPCLabs.KitServer.2", "Simulation.Random", 1000,
                        state: 1), // An integer we have chosen to identify the subscription
                    new DAItemGroupArguments("", "OPCLabs.KitServer.2", "Trends.Ramp (1 min)", 1000,
                        state: 2), // An integer we have chosen to identify the subscription
                    new DAItemGroupArguments("", "OPCLabs.KitServer.2", "Trends.Sine (1 min)", 1000,
                        state: 3), // An integer we have chosen to identify the subscription
                    new DAItemGroupArguments("", "OPCLabs.KitServer.2", "Simulation.Register_I4", 1000,
                        state: 4) // An integer we have chosen to identify the subscription
                });

                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...");
            }

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

            Console.WriteLine("Finished.");
        }

        // Item changed event handler
        static void client_StateAsInteger_ItemChanged(object sender, EasyDAItemChangedEventArgs eventArgs)
        {
            // Obtain the integer state we have passed in.
            var stateAsInteger = (int)eventArgs.Arguments.State;

            // Display the data
            if (eventArgs.Succeeded)
                Console.WriteLine($"{stateAsInteger}: {eventArgs.Vtq}");
            else
                Console.WriteLine($"{stateAsInteger} *** Failure: {eventArgs.ErrorMessageBrief}");
        }
    }
}

# This example shows how subscribe to changes of multiple items and display each change, identifying the different
# subscriptions by an integer.
#
# 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 .
# The QuickOPC package is needed. Install it using "pip install opclabs_quickopc".
import opclabs_quickopc
import time

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


# Item changed event handler.
def itemChanged(sender, eventArgs):
    # Obtain the integer state we have passed in.
    stateAsInteger = int(eventArgs.Arguments.State)
    if eventArgs.Succeeded:
        print(stateAsInteger, ': ', eventArgs.Vtq, sep='')
    else:
        print(stateAsInteger, ' *** Failure: ', eventArgs.ErrorMessageBrief, sep='')


# Instantiate the client object.
client = EasyDAClient()
# Hook events.
client.ItemChanged += itemChanged

print('Subscribing item changes...')
handleArray = IEasyDAClientExtension.SubscribeMultipleItems(client, [
    DAItemGroupArguments('', 'OPCLabs.KitServer.2', 'Simulation.Random', 1000,
                         1),    # an integer we have chosen to identify the subscription
    DAItemGroupArguments('', 'OPCLabs.KitServer.2', 'Trends.Ramp (1 min)', 1000,
                         2),    # an integer we have chosen to identify the subscription
    DAItemGroupArguments('', 'OPCLabs.KitServer.2', 'Trends.Sine (1 min)', 1000,
                         3),    # an integer we have chosen to identify the subscription
    DAItemGroupArguments('', 'OPCLabs.KitServer.2', 'Simulation.Register_I4', 1000,
                         4),    # an integer we have chosen to identify the subscription
    ])

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

print('Processing item change notifications for 1 minute...')
time.sleep(60)

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

client.ItemChanged -= itemChanged

print('Finished.')

' This example shows how subscribe to changes of multiple items and display each change, identifying the different
' subscriptions by an integer.
'
' Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .

Imports System.Threading
Imports OpcLabs.EasyOpc.DataAccess
Imports OpcLabs.EasyOpc.DataAccess.OperationModel

Namespace DataAccess._EasyDAClient
    Partial Friend Class SubscribeMultipleItems
        Public Shared Sub StateAsInteger()
            ' Instantiate the client object.
            Using client = New EasyDAClient()
                AddHandler client.ItemChanged, AddressOf client_StateAsInteger_ItemChanged

                Console.WriteLine("Subscribing...")
                Dim handleArray() As Integer = client.SubscribeMultipleItems(New DAItemGroupArguments() {
                    New DAItemGroupArguments("", "OPCLabs.KitServer.2", "Simulation.Random", 1000,
                        state:=1), ' An integer we have chosen to identify the subscription
                    New DAItemGroupArguments("", "OPCLabs.KitServer.2", "Trends.Ramp (1 min)", 1000,
                        state:=2), ' An integer we have chosen to identify the subscription
                    New DAItemGroupArguments("", "OPCLabs.KitServer.2", "Trends.Sine (1 min)", 1000,
                        state:=3), ' An integer we have chosen to identify the subscription
                    New DAItemGroupArguments("", "OPCLabs.KitServer.2", "Simulation.Register_I4", 1000,
                        state:=4) ' An integer we have chosen to identify the subscription
                    })

                For i As Integer = 0 To handleArray.Length - 1
                    Console.WriteLine($"handleArray[{i}]: {handleArray(i)}")
                Next i

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

                Console.WriteLine("Unsubscribing...")
            End Using

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

            Console.WriteLine("Finished.")
        End Sub

        ' Item changed event handler
        Private Shared Sub client_StateAsInteger_ItemChanged(ByVal sender As Object, ByVal eventArgs As EasyDAItemChangedEventArgs)
            ' Obtain the integer state we have passed in.
            Dim stateAsInteger As Integer = CInt(eventArgs.Arguments.State)

            If eventArgs.Succeeded Then
                Console.WriteLine($"{stateAsInteger}: {eventArgs.Vtq}")
            Else
                Console.WriteLine($"{stateAsInteger} *** Failure: {eventArgs.ErrorMessageBrief}")
            End If
        End Sub
    End Class
End Namespace

Examples - OPC Unified Architecture

Examples - OPC Unified Architecture - Identify subscriptions by an integer state

Conceptual

Use the state instead of handles to identify subscribed entities

OPC Classic Item Changed Event or Callback