OPC Studio User's Guide and Reference
IEasyUAServerConnectionMonitoring Interface
Members  Example 



OpcLabs.ServerOpcUA Assembly > OpcLabs.EasyOpc.UA.Services Namespace : IEasyUAServerConnectionMonitoring Interface
Provides methods and events to monitor the OPC UA client connections on the server side.
Syntax
'Declaration
 
<CLSCompliantAttribute(True)>
<ComVisibleAttribute(False)>
<ExceptionContractAnnotationAttribute(True)>
<ExceptionContractVerificationAttribute(True)>
Public Interface IEasyUAServerConnectionMonitoring 
   Inherits OpcLabs.BaseLib.ComponentModel.IReadOnlyStartable 
'Usage
 
Dim instance As IEasyUAServerConnectionMonitoring
[CLSCompliant(true)]
[ComVisible(false)]
[ExceptionContractAnnotation(true)]
[ExceptionContractVerification(true)]
public interface IEasyUAServerConnectionMonitoring : OpcLabs.BaseLib.ComponentModel.IReadOnlyStartable  
[CLSCompliant(true)]
[ComVisible(false)]
[ExceptionContractAnnotation(true)]
[ExceptionContractVerification(true)]
public interface class IEasyUAServerConnectionMonitoring : public OpcLabs.BaseLib.ComponentModel.IReadOnlyStartable  
Example
// This example shows how to monitor OPC UA client connections to the server.
// You can use any OPC UA client, including our Connectivity Explorer and OpcCmd utility, to connect to the server. 
//
// Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-OpcStudio/Latest/examples.html .
// OPC client, server and subscriber examples in C# on GitHub: https://github.com/OPCLabs/Examples-OPCStudio-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 Microsoft.Extensions.DependencyInjection;
using OpcLabs.EasyOpc.UA;
using OpcLabs.EasyOpc.UA.NodeSpace;
using OpcLabs.EasyOpc.UA.OperationModel;
using OpcLabs.EasyOpc.UA.Services;

namespace UAServerDocExamples._EasyUAServerConnectionMonitoring
{
    class ClientSessions
    {
        public static void Main1()
        {
            // Instantiate the server object.
            // By default, the server will run on endpoint URL "opc.tcp://localhost:48040/".
            var server = new EasyUAServer();

            // Define a data variable providing random integers.
            var random = new Random();
            server.Add(new UADataVariable("MyDataVariable").ReadValueFunction(() => random.Next()));

            // Obtain the server connection monitoring service.
            IEasyUAServerConnectionMonitoring serverConnectionMonitoring = server.GetService<IEasyUAServerConnectionMonitoring>();
            if (serverConnectionMonitoring is null)
            {
                Console.WriteLine("The server connection monitoring service is not available.");
                return;
            }

            // Hook events.
            serverConnectionMonitoring.ClientSessionConnected += ServerConnectionMonitoringOnClientSessionConnected;
            serverConnectionMonitoring.ClientSessionDisconnected += ServerConnectionMonitoringOnClientSessionDisconnected;

            // Start the server.
            Console.WriteLine("The server is starting...");
            server.Start();

            Console.WriteLine("The server is started.");
            Console.WriteLine();

            // Let the user decide when to stop.
            Console.WriteLine("Press Enter to stop the server...");
            Console.ReadLine();

            // Stop the server.
            Console.WriteLine("The server is stopping...");
            server.Stop();

            Console.WriteLine("The server is stopped.");
        }

        // Event handler for the ClientSessionConnected event.
        static private void ServerConnectionMonitoringOnClientSessionConnected(
            object sender, 
            EasyUAClientSessionConnectionEventArgs e)

        {
            var serverConnectionMonitoring = (IEasyUAServerConnectionMonitoring)sender;
            Console.WriteLine(
                $"A client session has connected to endpoint \"{e.EndpointUrlString}\". " + 
                $"There is now {serverConnectionMonitoring.ClientSessionCount} client session(s).");
        }

        // Event handler for the ClientSessionDisconnected event.
        static private void ServerConnectionMonitoringOnClientSessionDisconnected(
            object sender,
            EasyUAClientSessionConnectionEventArgs e)
        {
            var serverConnectionMonitoring = (IEasyUAServerConnectionMonitoring)sender;
            Console.WriteLine(
                $"A client session has disconnected from endpoint \"{e.EndpointUrlString}\". " + 
                $"There is now {serverConnectionMonitoring.ClientSessionCount} client session(s).");
        }
    }
}
' This example shows how to monitor OPC UA client connections to the server.
' You can use any OPC UA client, including our Connectivity Explorer and OpcCmd utility, to connect to the server. 
'
' 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
Imports Microsoft.Extensions.DependencyInjection
Imports OpcLabs.EasyOpc.UA
Imports OpcLabs.EasyOpc.UA.NodeSpace
Imports OpcLabs.EasyOpc.UA.OperationModel
Imports OpcLabs.EasyOpc.UA.Services

Namespace _EasyUAServerConnectionMonitoring
    Partial Friend Class ClientSessions
        Shared Sub Main1()
            ' Instantiate the server object.
            ' By default, the server will run on endpoint URL "opc.tcp://localhost:48040/".
            Dim server = New EasyUAServer()

            ' Define a data variable providing random integers.
            Dim random = New Random()
            server.Add(New UADataVariable("MyDataVariable").ReadValueFunction(Function() random.Next()))

            ' Obtain the server connection monitoring service.
            Dim serverConnectionMonitoring As IEasyUAServerConnectionMonitoring = server.GetService(Of IEasyUAServerConnectionMonitoring)
            If serverConnectionMonitoring Is Nothing Then
                Console.WriteLine("The server connection monitoring service is not available.")
                Exit Sub
            End If


            ' Hook events.
            AddHandler serverConnectionMonitoring.ClientSessionConnected, AddressOf ServerConnectionMonitoringOnClientSessionConnected
            AddHandler serverConnectionMonitoring.ClientSessionDisconnected, AddressOf ServerConnectionMonitoringOnClientSessionDisconnected

            ' Start the server.
            Console.WriteLine("The server is starting...")
            server.Start()

            Console.WriteLine("The server is started.")
            Console.WriteLine()

            ' Let the user decide when to stop.
            Console.WriteLine("Press Enter to stop the server...")
            Console.ReadLine()

            ' Stop the server.
            Console.WriteLine("The server is stopping...")
            server.Stop()

            Console.WriteLine("The server is stopped.")
        End Sub

        ' Event handler for the ClientSessionConnected event.
        Private Shared Sub ServerConnectionMonitoringOnClientSessionConnected(ByVal sender As Object, ByVal e As EasyUAClientSessionConnectionEventArgs)
            Dim serverConnectionMonitoring As IEasyUAServerConnectionMonitoring = sender
            Console.WriteLine(
                $"A client session has connected to endpoint ""{e.EndpointUrlString}"". " +
                $"There is now {serverConnectionMonitoring.ClientSessionCount} client session(s).")
        End Sub

        ' Event handler for the ClientSessionDisconnected event.
        Private Shared Sub ServerConnectionMonitoringOnClientSessionDisconnected(ByVal sender As Object, ByVal e As EasyUAClientSessionConnectionEventArgs)
            Dim serverConnectionMonitoring As IEasyUAServerConnectionMonitoring = sender
            Console.WriteLine(
                $"A client session has disconnected from endpoint ""{e.EndpointUrlString}"". " +
                $"There is now {serverConnectionMonitoring.ClientSessionCount} client session(s).")
        End Sub
    End Class
End Namespace
Requirements

Target Platforms: .NET Framework: Windows 10 (selected versions), Windows 11 (selected versions), Windows Server 2016, Windows Server 2022; .NET: Linux, macOS, Microsoft Windows

See Also