Examples - OPC Alarms&Events - Subscribe to events

.NET

// This example shows how to subscribe to events and display the event message with each notification. It also shows how to 
// unsubscribe afterwards.
//
// 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.Threading;
using OpcLabs.EasyOpc.AlarmsAndEvents;
using OpcLabs.EasyOpc.AlarmsAndEvents.OperationModel;

namespace DocExamples.AlarmsAndEvents._EasyAEClient
{
    partial class SubscribeEvents
    {
        public static void Main1()
        {
            // Instantiate the client object.
            using (var client = new EasyAEClient())
            {
                var eventHandler = new EasyAENotificationEventHandler(client_Notification);
                client.Notification += eventHandler;

                int handle = client.SubscribeEvents("", "OPCLabs.KitEventServer.2", 1000);

                Console.WriteLine("Processing event notifications for 1 minute...");
                Thread.Sleep(60 * 1000);

                client.UnsubscribeEvents(handle);
            }
        }

        // Notification event handler
        static void client_Notification(object sender, EasyAENotificationEventArgs e)
        {
            if (!e.Succeeded)
            {
                Console.WriteLine("*** Failure: {0}", e.ErrorMessageBrief);
                return;
            }
            if (!(e.EventData is null))
                Console.WriteLine(e.EventData.Message);
        }
    }
}

# This example shows how to subscribe to events and display the event message with each notification. It also shows how to 
# unsubscribe afterwards.
#
# 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.AlarmsAndEvents

# 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 EasyAEClient

# Notification event handler
Register-ObjectEvent -InputObject $client -EventName Notification -Action { 
    if (-not $EventArgs.Succeeded) {
        Write-Host "*** Failure: $($EventArgs.ErrorMessageBrief)"
        #return
    }
    if ($EventArgs.EventData -ne $null) {
        Write-Host $EventArgs.EventData.Message
    }
}

Write-Host "Subscribing events..."
$handle = [IEasyAEClientExtension]::SubscribeEvents($client, "", "OPCLabs.KitEventServer.2", 1000)

Write-Host "Processing event notifications for 1 minute..."
$stopwatch =  [System.Diagnostics.Stopwatch]::StartNew() 
while ($stopwatch.Elapsed.TotalSeconds -lt 60) {    
    Start-Sleep -Seconds 1
}

Write-Host "Unsubscribing events..."
$client.UnsubscribeEvents($handle)

Write-Host "Finished."

' This example shows how to subscribe to events and display the event message with each notification. It also shows how to 
' unsubscribe afterwards.
'
' 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.EasyOpc.AlarmsAndEvents
Imports OpcLabs.EasyOpc.AlarmsAndEvents.OperationModel

Namespace AlarmsAndEvents._EasyAEClient
    Partial Friend Class SubscribeEvents
        Public Shared Sub Main1()
            Using client = New EasyAEClient()
                Dim eventHandler = New EasyAENotificationEventHandler(AddressOf client_Notification)
                AddHandler client.Notification, eventHandler

                Dim handle As Integer = client.SubscribeEvents("", "OPCLabs.KitEventServer.2", 1000)

                Console.WriteLine("Processing event notifications for 1 minute...")
                Thread.Sleep(60 * 1000)

                client.UnsubscribeEvents(handle)
            End Using
        End Sub

        ' Notification event handler
        Private Shared Sub client_Notification(ByVal sender As Object, ByVal e As EasyAENotificationEventArgs)
            If Not e.Succeeded Then
                Console.WriteLine("*** Failure: {0}", e.ErrorMessageBrief)
                Exit Sub
            End If
            If e.EventData IsNot Nothing Then
                Console.WriteLine(e.EventData.Message)
            End If
        End Sub
    End Class
End Namespace

COM

// This example shows how to subscribe to events and display the event message with each notification. It also shows how to
// unsubscribe afterwards.
//
// Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .
// OPC client and subscriber examples in Object Pascal (Delphi) on GitHub: https://github.com/OPCLabs/Examples-QuickOPC-OP .
// 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.

type
  TClientEventHandlers = class
    // Notification event handler
    procedure OnNotification(
      ASender: TObject;
      sender: OleVariant;
      const eventArgs: _EasyAENotificationEventArgs);
  end;

procedure TClientEventHandlers.OnNotification(
  ASender: TObject;
  sender: OleVariant;
  const eventArgs: _EasyAENotificationEventArgs);
begin
  if not eventArgs.Succeeded then
    WriteLn(Format('*** Failure: %s', [eventArgs.ErrorMessageBrief]));
  if eventArgs.EventData <> nil then
      WriteLn(eventArgs.EventData.Message);
end;

class procedure SubscribeEvents.Main;
var
  Client: TEasyAEClient;
  ClientEventHandlers: TClientEventHandlers;
  Handle: Integer;
  ServerDescriptor: _ServerDescriptor;
  State: OleVariant;
  SubscriptionParameters: _AESubscriptionParameters;
begin
  ServerDescriptor := CoServerDescriptor.Create;
  ServerDescriptor.ServerClass := 'OPCLabs.KitEventServer.2';

  // Instantiate the client object and hook events
  Client := TEasyAEClient.Create(nil);
  ClientEventHandlers := TClientEventHandlers.Create;
  Client.OnNotification := ClientEventHandlers.OnNotification;

  WriteLn('Subscribing events...');
  SubscriptionParameters := CoAESubscriptionParameters.Create;
  SubscriptionParameters.NotificationRate := 1000;
  Handle := Client.SubscribeEvents(ServerDescriptor, SubscriptionParameters, true, State);

  WriteLn('Processing event notifications for 1 minute...');
  PumpSleep(60*1000);

  WriteLn('Unsubscribing events...');
  Client.UnsubscribeEvents(Handle);

  WriteLn('Finished.');
  FreeAndNil(Client);
  FreeAndNil(ClientEventHandlers);
end;

// This example shows how to subscribe to events and display the event message with each notification. It also shows how to
// unsubscribe afterwards.
//
// 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.

class DEasyEAClientEvents {
    function Notification($Sender, $E)
    {
        if (!($E->Succeeded))
        {
            printf("*** Failure: %s\n", $E->ErrorMessageBrief);
            Exit();
        }

        if (!is_null($E->EventData))
        {
            print $E->EventData->Message;
            print "\n";
        }
    }
}

$ServerDescriptor = new COM("OpcLabs.EasyOpc.ServerDescriptor");
$ServerDescriptor->ServerClass = "OPCLabs.KitEventServer.2";

$Client = new COM("OpcLabs.EasyOpc.AlarmsAndEvents.EasyAEClient");
$Events = new DEasyEAClientEvents();
com_event_sink($Client, $Events, "DEasyEAClientEvents");

print "Subscribing events...\n";
$SubscriptionParameters = new COM("OpcLabs.EasyOpc.AlarmsAndEvents.AESubscriptionParameters");
$SubscriptionParameters->NotificationRate = 1000;
$handle = $Client->SubscribeEvents($ServerDescriptor, $SubscriptionParameters, TRUE, NULL);

print "Processing event notifications for 1 minute...\n";
$startTime = time(); do { com_message_pump(1000); } while (time() < $startTime + 60);

print "Unsubscribing events...\n";
$Client->UnsubscribeEvents($handle);

print "Finished.\n";

REM This example shows how to subscribe to events and display the event message with each notification. It also shows how to
REM unsubscribe afterwards.
REM
REM Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .
REM OPC client and subscriber examples in Visual Basic on GitHub: https://github.com/OPCLabs/Examples-QuickOPC-VB .
REM Missing some example? Ask us for it on our Online Forums, https://www.opclabs.com/forum/index ! You do not have to own
REM a commercial license in order to use Online Forums, and we reply to every post.

Private Sub SubscribeEvents_Main_Command_Click()
    OutputText = ""
    
    Dim serverDescriptor As New serverDescriptor
    serverDescriptor.ServerClass = "OPCLabs.KitEventServer.2"
    
    ' Instantiate the client object and hook events
    Set Client1 = New EasyAEClient
    
    OutputText = OutputText & "Subscribing..." & vbCrLf
    Dim subscriptionParameters As New AESubscriptionParameters
    subscriptionParameters.notificationRate = 1000
    Dim handle
    Dim state
    handle = Client1.SubscribeEvents(serverDescriptor, subscriptionParameters, True, state)

    OutputText = OutputText & "Processing event notifications for 1 minute..." & vbCrLf
    Pause 60000

    OutputText = OutputText & "Unsubscribing events..." & vbCrLf
    Client1.UnsubscribeEvents handle

    OutputText = OutputText & "Waiting for 5 seconds..." & vbCrLf
    Pause 5000

    OutputText = OutputText & "Finished." & vbCrLf

    Set Client1 = Nothing
End Sub

Private Sub Client1_OnNotification(ByVal sender As Variant, ByVal eventArgs As EasyAENotificationEventArgs)
    If Not eventArgs.Succeeded Then
        OutputText = OutputText & eventArgs.ErrorMessageBrief & vbCrLf
        Exit Sub
    End If
    If Not eventArgs.EventData Is Nothing Then
        OutputText = OutputText & eventArgs.EventData.Message & vbCrLf
    End If
End Sub

Rem This example shows how to subscribe to events and display the event message with each notification. It also shows how to
Rem unsubscribe afterwards.
Rem
Rem Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .
Rem OPC client and subscriber examples in VBScript on GitHub: https://github.com/OPCLabs/Examples-QuickOPC-VBScript .
Rem Missing some example? Ask us for it on our Online Forums, https://www.opclabs.com/forum/index ! You do not have to own
Rem a commercial license in order to use Online Forums, and we reply to every post.

Option Explicit

Dim ServerDescriptor: Set ServerDescriptor = CreateObject("OpcLabs.EasyOpc.ServerDescriptor")
ServerDescriptor.ServerClass = "OPCLabs.KitEventServer.2"

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

WScript.Echo "Subscribing events..."
Dim SubscriptionParameters: Set SubscriptionParameters = CreateObject("OpcLabs.EasyOpc.AlarmsAndEvents.AESubscriptionParameters")
SubscriptionParameters.NotificationRate = 1000
Dim handle: handle = Client.SubscribeEvents(ServerDescriptor, SubscriptionParameters, True, Nothing)

WScript.Echo "Processing event notifications for 1 minute..."
WScript.Sleep 60*1000

WScript.Echo "Unsubscribing events..."
Client.UnsubscribeEvents handle

WScript.Echo "Finished."



Rem Notification event handler
Sub Client_Notification(Sender, e)
    If Not e.Succeeded Then
        WScript.Echo "*** Failure: " & e.ErrorMessageBrief
        Exit Sub
    End If

    If Not e.EventData Is Nothing Then WScript.Echo e.EventData.Message
End Sub

Python

Python (.NET)

# This example shows how to subscribe to events and display the event message with each notification. It also shows how
# to unsubscribe afterwards.
#
# 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 time

# Import .NET namespaces.
from OpcLabs.EasyOpc import *
from OpcLabs.EasyOpc.AlarmsAndEvents import *


# Notification event handler
def notification(sender, e):
    if not e.Succeeded:
        print('*** Failure: ', e.ErrorMessageBrief, sep='')
        return
    else:
        if e.EventData is not None:
            print(e.EventData.Message)


# Instantiate the client object
client = EasyAEClient()

client.Notification += notification

print('Subscribing events...')
handle = IEasyAEClientExtension.SubscribeEvents(client, '', 'OPCLabs.KitEventServer.2', 1000)

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

print('Unsubscribing events...')
client.UnsubscribeAllEvents()

client.Notification -= notification

print('Finished.')

.NET

COM

Python

Concepts

Examples - Client OPC UA Alarms&Conditions

Examples - Client Reactive Programming

Installed Examples - Client Console