Examples - Sparkplug Edge Node - Implement reading a value using a function

.NET

C#
VB.NET

// This example shows how to create a metric and implement reading its value using a function.
//
// You can use any Sparkplug application, including our SparkplugCmd utility and the SparkplugApplicationConsoleDemo
// program, to subscribe to the edge node data. 
//
// Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-ConnectivityStudio/Latest/examples.html .
// Sparkplug examples in C# on GitHub: https://github.com/OPCLabs/Examples-ConnectivityStudio-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 OpcLabs.EasySparkplug;
using System;

namespace SparkplugDocExamples.EdgeNode._SparkplugMetric
{
    partial class ReadValueFunction
    {
        static public void Main1()
        {
            // Note that the default port for the "mqtt" scheme is 1883.
            var hostDescriptor = new SparkplugHostDescriptor("mqtt://localhost");

            // Instantiate the edge node object and hook events.
            var edgeNode = new EasySparkplugEdgeNode(hostDescriptor, "easyGroup", "easySparkplugDemo");
            edgeNode.SystemConnectionStateChanged += (sender, eventArgs) =>
            {
                // Display the new connection state (such as when the connection to the broker succeeds or fails).
                Console.WriteLine($"{nameof(EasySparkplugEdgeNode.SystemConnectionStateChanged)}: {eventArgs}");
            };

            // Create a metric, defining its read values by a function.
            // The type of the metric (Int32, in this case) is inferred from the type returned by the function.
            var random = new Random();
            edgeNode.Add(new SparkplugMetric("ReadThisMetric").ReadValueFunction(() => random.Next()));

            // Start the edge node.
            Console.WriteLine("The edge node is starting...");
            edgeNode.Start();

            Console.WriteLine("The edge node is started.");
            Console.WriteLine();

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

            // Stop the edge node.
            Console.WriteLine("The edge node is stopping...");
            edgeNode.Stop();

            Console.WriteLine("The edge node is stopped.");
        }
    }
}

' This example shows how to create a metric and implement reading its value using a function.
'
' You can use any Sparkplug application, including our SparkplugCmd utility and the SparkplugApplicationConsoleDemo
' program, to subscribe to the edge node data.
'
' Find all latest examples here: https://opclabs.doc-that.com/files/onlinedocs/OPCLabs-ConnectivityStudio/Latest/examples.html .
' Sparkplug examples in C# on GitHub: https://github.com/OPCLabs/Examples-ConnectivityStudio-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.

Imports OpcLabs.EasySparkplug

Namespace Global.SparkplugDocExamples.EdgeNode._SparkplugMetric
    Partial Class ReadValueFunction
        Public Shared Sub Main1()
            ' Note that the default port for the "mqtt" scheme is 1883.
            Dim hostDescriptor = New SparkplugHostDescriptor("mqtt://localhost")

            ' Instantiate the edge node object and hook events.
            Dim edgeNode = New EasySparkplugEdgeNode(hostDescriptor, "easyGroup", "easySparkplugDemo")
            AddHandler edgeNode.SystemConnectionStateChanged,
                Sub(sender, eventArgs)
                    ' Display the new connection state (such as when the connection to the broker succeeds or fails).
                    Console.WriteLine($"{NameOf(EasySparkplugEdgeNode.SystemConnectionStateChanged)}: {eventArgs}")
                End Sub

            ' Create a metric, defining its read values by a function.
            ' The type of the metric (Int32, in this case) is inferred from the type returned by the function.
            Dim random = New Random()
            edgeNode.Add(New SparkplugMetric("ReadThisMetric").ReadValueFunction(Function() random.Next()))

            ' Start the edge node.
            Console.WriteLine("The edge node is starting...")
            edgeNode.Start()

            Console.WriteLine("The edge node is started.")
            Console.WriteLine()

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

            ' Stop the edge node.
            Console.WriteLine("The edge node is stopping...")
            edgeNode.Stop()

            Console.WriteLine("The edge node is stopped.")
        End Sub
    End Class
End Namespace

Reference

ReadValueFunction Method

Rapid Toolkit for Sparkplug

Sparkplug Metric Configuration