IEasyUAClientConnectionControlExtension Class

Contains extension methods to the OpcLabs.EasyOpc.UA.Services.IEasyUAClientConnectionControl interface.

Syntax

Visual Basic
C#
C++/CLI

'Declaration
 
<ExtensionAttribute()>
<ComVisibleAttribute(False)>
<ExceptionContractAnnotationAttribute(True)>
<ExceptionContractVerificationAttribute(True)>
Public MustInherit NotInheritable Class IEasyUAClientConnectionControlExtension

'Usage
 
Dim instance As IEasyUAClientConnectionControlExtension

[Extension()]
[ComVisible(false)]
[ExceptionContractAnnotation(true)]
[ExceptionContractVerification(true)]
public static class IEasyUAClientConnectionControlExtension

[Extension()]
[ComVisible(false)]
[ExceptionContractAnnotation(true)]
[ExceptionContractVerification(true)]
public ref class IEasyUAClientConnectionControlExtension abstract sealed

Remarks

This class contains extension methods (info: C#, VB.NET). In languages that have support for extensions methods (such as C# and VB.NET), you can use the extension method as if it were a regular method on the object that is its first parameter. In other languages (such as with Python.NET), you will call the extension as a static method, and pass it the object on which it acts as its first parameter.

Example

CSharp
VB.NET

// This example shows how to obtain lock the OPC UA connection and obtain a disposable object which unlocks the connection
// when it is disposed.
//
// 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 Microsoft.Extensions.DependencyInjection;
using OpcLabs.EasyOpc.UA;
using OpcLabs.EasyOpc.UA.OperationModel;
using OpcLabs.EasyOpc.UA.Services;
using OpcLabs.EasyOpc.UA.Services.Extensions;

namespace UADocExamples._EasyUAClientConnectionControl
{
    class DisposableLockConnection
    {
        public static void Main1()
        {
            UAEndpointDescriptor endpointDescriptor =
                "opc.tcp://opcua.demo-this.com:51210/UA/SampleServer";
            // or "http://opcua.demo-this.com:51211/UA/SampleServer" (currently not supported)
            // or "https://opcua.demo-this.com:51212/UA/SampleServer/"

            // Instantiate the client object and hook events
            using (var client = new EasyUAClient())
            {
                // Obtain the client connection monitoring service.
                IEasyUAClientConnectionMonitoring clientConnectionMonitoring = client.GetService<IEasyUAClientConnectionMonitoring>();
                if (clientConnectionMonitoring is null)
                {
                    Console.WriteLine("The client connection monitoring service is not available.");
                    return;
                }

                // Obtain the client connection control service.
                IEasyUAClientConnectionControl clientConnectionControl = client.GetService<IEasyUAClientConnectionControl>();
                if (clientConnectionControl is null)
                {
                    Console.WriteLine("The client connection control service is not available.");
                    return;
                }

                // Display the server condition changed events.
                clientConnectionMonitoring.ServerConditionChanged += (sender, args) => Console.WriteLine(args);

                try
                {
                    Console.WriteLine("Reading (1)");
                    // The first read will cause a connection to the server.
                    UAAttributeData attributeData1 =
                        client.Read(endpointDescriptor, "nsu=http://test.org/UA/Data/ ;i=10853");
                    Console.WriteLine(attributeData1);

                    Console.WriteLine("Waiting for 10 seconds...");
                    // Since the connection is now not used for some time, and it is not locked, it will be closed.
                    System.Threading.Thread.Sleep(10 * 1000);

                    Console.WriteLine("Locking");
                    // Locking the connection causes it to open, if possible.
                    using (clientConnectionControl.DisposableLockConnection(endpointDescriptor))
                    {
                        Console.WriteLine("Waiting for 10 seconds...");
                        // The connection is locked, it will not be closed now.
                        System.Threading.Thread.Sleep(10 * 1000);

                        Console.WriteLine("Reading (2)");
                        UAAttributeData attributeData2 =
                            client.Read(endpointDescriptor, "nsu=http://test.org/UA/Data/ ;i=10853");
                        Console.WriteLine(attributeData2);

                        Console.WriteLine("Waiting for 10 seconds...");
                        // The connection is still locked, it will not be closed now.
                        System.Threading.Thread.Sleep(10 * 1000);

                        // Unlocking will occur now.
                    }
                    Console.WriteLine("Unlocked");
                }
                catch (UAException uaException)
                {
                    Console.WriteLine("*** Failure: {0}", uaException.GetBaseException().Message);
                }

                Console.WriteLine("Waiting for 10 seconds...");
                // After some delay, the connection will be closed, because there are no subscriptions to the server and no
                // connection locks.
                System.Threading.Thread.Sleep(10 * 1000);

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


        // Example output:
        //
        //Reading (1)
        //"opc.tcp://opcua.demo-this.com:51210/UA/SampleServer" Connecting; Success; Attempt #1
        //"opc.tcp://opcua.demo-this.com:51210/UA/SampleServer" Connected; Success
        //-1.034588E+18 {Single} @2021-11-15T15:26:39.169 @@2021-11-15T15:26:39.169; Good
        //Waiting for 10 seconds...
        //"opc.tcp://opcua.demo-this.com:51210/UA/SampleServer" Disconnecting; Success
        //"opc.tcp://opcua.demo-this.com:51210/UA/SampleServer" Disconnected(RetrialDelay=Infinite); Success
        //Locking
        //"opc.tcp://opcua.demo-this.com:51210/UA/SampleServer" Connecting; Success; Attempt #1
        //"opc.tcp://opcua.demo-this.com:51210/UA/SampleServer" Connected; Success
        //Waiting for 10 seconds...
        //Reading (2)
        //2.288872E+21 {Single} @2021-11-15T15:26:59.836 @@2021-11-15T15:26:59.836; Good
        //Waiting for 10 seconds...
        //Unlocked
        //Waiting for 10 seconds...
        //"opc.tcp://opcua.demo-this.com:51210/UA/SampleServer" Disconnecting; Success
        //"opc.tcp://opcua.demo-this.com:51210/UA/SampleServer" Disconnected(RetrialDelay=Infinite); Success
        //Finished.
    }
}

' This example shows how to obtain lock the OPC UA connection and obtain a disposable object which unlocks the connection
' when it is disposed.
'
' 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 Microsoft.Extensions.DependencyInjection
Imports OpcLabs.EasyOpc.UA
Imports OpcLabs.EasyOpc.UA.OperationModel
Imports OpcLabs.EasyOpc.UA.Services
Imports OpcLabs.EasyOpc.UA.Services.Extensions

Namespace _EasyUAClientConnectionControl
    Partial Friend Class DisposableLockConnection
        Public Shared Sub Main1()
            Dim endpointDescriptor As UAEndpointDescriptor =
                    "opc.tcp://opcua.demo-this.com:51210/UA/SampleServer"
            ' or "http://opcua.demo-this.com:51211/UA/SampleServer" (currently not supported)
            ' or "https://opcua.demo-this.com:51212/UA/SampleServer/"

            ' Instantiate the client object and hook events
            Using client = New EasyUAClient()
                ' Obtain the client connection monitoring service.
                Dim clientConnectionMonitoring As IEasyUAClientConnectionMonitoring = client.GetService(Of IEasyUAClientConnectionMonitoring)
                If clientConnectionMonitoring Is Nothing Then
                    Console.WriteLine("The client connection monitoring service is not available.")
                    Exit Sub
                End If

                ' Obtain the client connection control service.
                Dim clientConnectionControl As IEasyUAClientConnectionControl = client.GetService(Of IEasyUAClientConnectionControl)
                If clientConnectionControl Is Nothing Then
                    Console.WriteLine("The client connection control service is not available.")
                    Exit Sub
                End If

                ' Display the server condition changed events.
                AddHandler clientConnectionMonitoring.ServerConditionChanged, Sub(sender, args)
                                                                                  Console.WriteLine(args)
                                                                              End Sub
                Try
                    Console.WriteLine("Reading (1)")
                    ' The first read will cause a connection to the server.
                    Dim attributeData1 As UAAttributeData =
                        client.Read(endpointDescriptor, "nsu=http://test.org/UA/Data/ ;i=10853")
                    Console.WriteLine(attributeData1)

                    Console.WriteLine("Waiting for 10 seconds...")
                    ' Since the connection is now not used for some time, and it is not locked, it will be closed.
                    System.Threading.Thread.Sleep(10 * 1000)

                    Console.WriteLine("Locking")
                    ' Locking the connection causes it to open, if possible.

                    Using clientConnectionControl.DisposableLockConnection(endpointDescriptor)
                        Console.WriteLine("Waiting for 10 seconds...")
                        ' The connection is locked, it will Not be closed now.
                        System.Threading.Thread.Sleep(10 * 1000)

                        Console.WriteLine("Reading (2)")
                        Dim attributeData2 As UAAttributeData =
                            client.Read(endpointDescriptor, "nsu=http://test.org/UA/Data/ ;i=10853")
                        Console.WriteLine(attributeData2)

                        Console.WriteLine("Waiting for 10 seconds...")
                        ' The connection is still locked, it will not be closed now.
                        System.Threading.Thread.Sleep(10 * 1000)

                        ' Unlocking will occur now.
                    End Using
                    Console.WriteLine("Unlocked")
                Catch uaException As UAException
                    Console.WriteLine("*** Failure: {0}", uaException.GetBaseException().Message)
                End Try

                Console.WriteLine("Waiting for 10 seconds...")
                ' After some delay, the connection will be closed, because there are no subscriptions to the server and no
                ' connection locks.
                System.Threading.Thread.Sleep(10 * 1000)

                Console.WriteLine("Finished.")
            End Using
        End Sub

        ' Example output
        '
        'Reading (1)
        '"opc.tcp://opcua.demo-this.com:51210/UA/SampleServer" Connecting; Success; Attempt #1
        '"opc.tcp://opcua.demo-this.com:51210/UA/SampleServer" Connected; Success
        '-1.034588E+18 {Single} @2021-11-15T15:26:39.169 @@2021-11-15T15:26:39.169; Good
        'Waiting for 10 seconds...
        '"opc.tcp://opcua.demo-this.com:51210/UA/SampleServer" Disconnecting; Success
        '"opc.tcp://opcua.demo-this.com:51210/UA/SampleServer" Disconnected(RetrialDelay=Infinite); Success
        'Locking
        '"opc.tcp://opcua.demo-this.com:51210/UA/SampleServer" Connecting; Success; Attempt #1
        '"opc.tcp://opcua.demo-this.com:51210/UA/SampleServer" Connected; Success
        'Waiting for 10 seconds...
        'Reading (2)
        '2.288872E+21 {Single} @2021-11-15T15:26:59.836 @@2021-11-15T15:26:59.836; Good
        'Waiting for 10 seconds...
        'Unlocked
        'Waiting for 10 seconds...
        '"opc.tcp://opcua.demo-this.com:51210/UA/SampleServer" Disconnecting; Success
        '"opc.tcp://opcua.demo-this.com:51210/UA/SampleServer" Disconnected(RetrialDelay=Infinite); Success
        'Finished.
    End Class
End Namespace

Inheritance Hierarchy

System.Object
OpcLabs.EasyOpc.UA.Services.Extensions.IEasyUAClientConnectionControlExtension

Requirements

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

Reference

IEasyUAClientConnectionControlExtension Members
OpcLabs.EasyOpc.UA.Services.Extensions Namespace

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