Isolated Property (EasyDAClientCore)

Specifies that you wish that the EasyDAClientCore object instance works with an "isolated" connection to the OPC server, i.e. one that is not shared with other instances.

Syntax

Visual Basic
C#
C++/CLI

'Declaration
 
Public Property Isolated As Boolean

'Usage
 
Dim instance As EasyDAClientCore
Dim value As Boolean
 
instance.Isolated = value
 
value = instance.Isolated

public bool Isolated {get; set;}

public:
property bool Isolated {
   bool get();
   void set (    bool value);
}

Remarks

This method or property does not throw any exceptions, aside from execution exceptions such as System.Threading.ThreadAbortException or System.OutOfMemoryException.

Example

// This example shows how to create and use two isolated client objects, resulting in two separate connections to the target
// OPC DA server.

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

namespace DocExamples.DataAccess._EasyDAClient
{
    class Isolated
    {
        public static void Main1()
        {
            // Instantiate the client objects and make them isolated
            var client1 = new EasyDAClient { Isolated = true };
            var client2 = new EasyDAClient { Isolated = true };

            // The callback is a local method the displays the value
            void ItemChangedCallback(object sender, EasyDAItemChangedEventArgs eventArgs)
            {
                Debug.Assert(!(eventArgs is null));

                Console.Write($"[{eventArgs.Arguments.State}] ");
                if (eventArgs.Succeeded)
                {
                    Debug.Assert(!(eventArgs.Vtq is null));
                    Console.WriteLine(eventArgs.Vtq.ToString());
                }
                else
                    Console.WriteLine("*** Failure: {0}", eventArgs.ErrorMessageBrief);
            }

            Console.WriteLine("Subscribing...");
            client1.SubscribeItem("", "OPCLabs.KitServer.2", "Simulation.Random", 1000, ItemChangedCallback, state: 1);
            client2.SubscribeItem("", "OPCLabs.KitServer.2", "Simulation.Random", 1000, ItemChangedCallback, state: 2);

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

            Console.WriteLine("Unsubscribing...");
            client1.UnsubscribeAllItems();
            client2.UnsubscribeAllItems();

            Console.WriteLine("Waiting for 2 seconds...");
            Thread.Sleep(2 * 1000);
        }
    }
}

# This example shows how to create and use two isolated client objects, resulting in two separate connections to the
# target OPC DA server.

# 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 *


# Item changed event handler
def itemChangedCallback(sender, eventArgs):
    assert eventArgs is not None
    print('[', eventArgs.Arguments.State, '] ', sep='', end='')
    if eventArgs.Succeeded:
        assert eventArgs.Vtq is not None
        print(eventArgs.Vtq)
    else:
        print('*** Failure: ', eventArgs.ErrorMessageBrief, sep='')


# Instantiate the client objects and make them isolated.
client1 = EasyDAClient()
client1.Isolated = True
client2 = EasyDAClient()
client2.Isolated = True

print('Subscribing item changes...')
IEasyDAClientExtension.SubscribeItem(client1,
                                     '', 'OPCLabs.KitServer.2', 'Simulation.Random', 1000,
                                     EasyDAItemChangedEventHandler(itemChangedCallback), 1)
IEasyDAClientExtension.SubscribeItem(client2,
                                     '', 'OPCLabs.KitServer.2', 'Simulation.Random', 1000,
                                     EasyDAItemChangedEventHandler(itemChangedCallback), 2)

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

print('Unsubscribing all items...')
client1.UnsubscribeAllItems()
client2.UnsubscribeAllItems()

print('Waiting for 2 seconds...')
time.sleep(2)

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

EasyDAClientCore Class
EasyDAClientCore Members

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