Installed Examples - Console

The example below logs OPC Data Access item changes into an XML file.

The main program:

C#
VB.NET

// Logs OPC Data Access item changes into an XML file.
//
// Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .

using System;
using System.Diagnostics;
using System.Xml;
using System.Xml.Serialization;
using OpcLabs.BaseLib.Runtime.InteropServices;
using OpcLabs.EasyOpc.DataAccess;
using OpcLabs.EasyOpc.DataAccess.OperationModel;

namespace XmlLogger
{
    class Program
    {
        static void Main()
        {
            ComManagement.Instance.AssureSecurityInitialization();

            Console.WriteLine("Starting up...");
            var xmlSerializer = new XmlSerializer(typeof(EasyDAItemChangedEventArgs));
            var xmlWriter = XmlWriter.Create("OpcData.xml", new XmlWriterSettings
                                        {
                                            Indent = true,
                                            CloseOutput = true
                                        });
            // The root element can have any name you need, but the name below also allows reading the log back as .NET array
            xmlWriter.WriteStartElement("ArrayOfEasyDAItemChangedEventArgs");

            Console.WriteLine("Logging data for 30 seconds...");
            int handle = EasyDAClient.SharedInstance.SubscribeItem("", "OPCLabs.KitServer.2", 
                "Simulation.Incrementing (1 s)", 100,
               (_, eventArgs) =>
                   {
                       Debug.Assert(!(eventArgs is null));
                       Console.Write(".");
                       xmlSerializer.Serialize(xmlWriter, eventArgs);
                   });
            System.Threading.Thread.Sleep(30 * 1000);

            Console.WriteLine();
            Console.WriteLine("Shutting down...");
            EasyDAClient.SharedInstance.UnsubscribeItem(handle);
            xmlWriter.WriteEndElement();    // not really necessary - XmlWriter would write the end tag for us anyway
            xmlWriter.Close();

            Console.WriteLine("Finished.");
        }
    }
}

' Logs OPC Data Access item changes into an XML file.
'
' Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .

Imports System.Xml
Imports System.Xml.Serialization
Imports OpcLabs.BaseLib.Runtime.InteropServices
Imports OpcLabs.EasyOpc.DataAccess
Imports OpcLabs.EasyOpc.DataAccess.OperationModel


Friend Class Program
    Shared WithEvents _client As New EasyDAClient
    Shared ReadOnly XmlSerializer As New XmlSerializer(GetType(EasyDAItemChangedEventArgs))
    Shared _xmlWriter As XmlWriter

    <MTAThread> ' needed for COM security initialization to succeed
    Shared Sub Main()
        ComManagement.Instance.AssureSecurityInitialization()

        Console.WriteLine("Starting up...")
        _xmlWriter = XmlWriter.Create("OpcData.xml", New XmlWriterSettings With {.Indent = True, .CloseOutput = True})
        ' The root element can have any name you need, but the name below also allows reading the log back as .NET array
        _xmlWriter.WriteStartElement("ArrayOfEasyDAItemChangedEventArgs")

        Console.WriteLine("Logging data for 30 seconds...")
        Dim handle As Integer = _client.SubscribeItem(
            "",
            "OPCLabs.KitServer.2",
            "Simulation.Incrementing (1 s)",
            100)
        Threading.Thread.Sleep(30 * 1000)

        Console.WriteLine()
        Console.WriteLine("Shutting down...")
        _client.UnsubscribeItem(handle)
        _xmlWriter.WriteEndElement() ' not really necessary - XmlWriter would write the end tag for us anyway
        _xmlWriter.Close()

        Console.WriteLine("Finished.")
    End Sub

    Private Shared Sub ItemChanged(ByVal sender As Object, ByVal eventArgs As EasyDAItemChangedEventArgs) Handles _client.ItemChanged
        Debug.Assert(eventArgs IsNot Nothing)
        Console.Write(".")
        XmlSerializer.Serialize(_xmlWriter, eventArgs)
    End Sub
End Class

Conceptual

Examples for OPC “Classic” (OPC-DA, OPC XML-DA and OPC-A&E)

Subscribing to OPC Classic Items

Examples - OPC Data Access

Examples - OPC Data Access - Subscribe to a single item