// This example shows how to subscribe to events and display the event message with each notification, using a callback method // specified using lambda expression. // // 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.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 callback method ' specified using lambda expression. ' ' 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 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
# This example shows how to subscribe to events and display the event message with each notification, using a regular # callback method. # # 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 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.')
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