// This example shows how to subscribe to events and display the event message with each notification, using a callback method
// specified using lambda expression.
using System;
using System.Diagnostics;
using System.Threading;
using OpcLabs.EasyOpc.AlarmsAndEvents;
namespace DocExamples.AlarmsAndEvents._EasyAEClient
{
partial class SubscribeEvents
{
public static void CallbackLambda()
{
// Instantiate the client object.
var client = new EasyAEClient();
Console.WriteLine("Subscribing...");
// The callback is a lambda expression the displays the event message
client.SubscribeEvents("", "OPCLabs.KitEventServer.2", 1000,
(sender, eventArgs) =>
{
Debug.Assert(eventArgs != null);
if (!eventArgs.Succeeded)
{
Console.WriteLine("*** Failure: {0}", eventArgs.ErrorMessageBrief);
return;
}
if (!(eventArgs.EventData is null))
Console.WriteLine(eventArgs.EventData.Message);
});
Console.WriteLine("Processing event notifications for 20 seconds...");
Thread.Sleep(20 * 1000);
Console.WriteLine("Unsubscribing...");
client.UnsubscribeAllEvents();
Console.WriteLine("Waiting for 2 seconds...");
Thread.Sleep(2 * 1000);
}
}
}
# This example shows how to subscribe to events and display the event message with each notification, using a regular
# callback method.
# 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 callback.
def callback(sender, e):
assert e is not None
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()
print('Subscribing events...')
# The callback is a regular method that displays the event message.
handle = IEasyAEClientExtension.SubscribeEvents(client,
'', 'OPCLabs.KitEventServer.2', 1000,
EasyAENotificationEventHandler(callback))
print('Processing event notifications for 20 seconds...')
time.sleep(20)
print('Unsubscribing events...')
client.UnsubscribeAllEvents()
print('Waiting for 2 seconds...')
time.sleep(2)
print('Finished.')
' This example shows how to subscribe to events and display the event message with each notification, using a callback method
' specified using lambda expression.
Imports OpcLabs.EasyOpc.AlarmsAndEvents
Namespace AlarmsAndEvents._EasyAEClient
Partial Friend Class SubscribeEvents
Public Shared Sub CallbackLambda()
' Instantiate the client object
Dim client = New EasyAEClient()
Console.WriteLine("Subscribing...")
' The callback is a lambda expression the displays the event message
client.SubscribeEvents("", "OPCLabs.KitEventServer.2", 1000,
Sub(sender, eventArgs)
Debug.Assert(eventArgs IsNot Nothing)
If Not eventArgs.Succeeded Then
Console.WriteLine("*** Failure: {0}", eventArgs.ErrorMessageBrief)
Exit Sub
End If
If eventArgs.EventData IsNot Nothing Then
Console.WriteLine(eventArgs.EventData.Message)
End If
End Sub)
Console.WriteLine("Processing event notifications for 20 seconds...")
Threading.Thread.Sleep(20 * 1000)
Console.WriteLine("Unsubscribing...")
client.UnsubscribeAllEvents()
Console.WriteLine("Waiting for 2 seconds...")
Threading.Thread.Sleep(2 * 1000)
End Sub
End Class
End Namespace
