Develop the publisher NetLogic and interface

Develop a NetLogic and integrate it with the interface.

Develop the NetLogic

In Project view, expand UI.
Right-click MainWindow (type) and select New > Runtime NetLogic.
Hover-over the NetLogic, select , and enter PublisherLogic.
Double-click the NetLogic.
The external code editor opens.

In the code editor, replace the existing code with the following code:

#region StandardUsing
using System;
using FTOptix.CoreBase;
using FTOptix.HMIProject;
using UAManagedCore;
using OpcUa = UAManagedCore.OpcUa;
using FTOptix.NetLogic;
using FTOptix.UI;
using FTOptix.OPCUAServer;
#endregion
using uPLibrary.Networking.M2Mqtt;
using uPLibrary.Networking.M2Mqtt.Messages;

public class PublisherLogic : BaseNetLogic
{
    public override void Start()
    {
        var brokerIpAddressVariable = Project.Current.GetVariable("Model/BrokerIpAddress");

        // Create a client connecting to the broker (default port is 1883)
        publishClient = new MqttClient(brokerIpAddressVariable.Value);
        // Connect to the broker
        publishClient.Connect("PublisherClient");
        // Assign a callback to be executed when a message is published to the broker
        publishClient.MqttMsgPublished += PublishClientMqttMsgPublished;
    }

    public override void Stop()
    {
        publishClient.Disconnect();
        publishClient.MqttMsgPublished -= PublishClientMqttMsgPublished;
    }

    private void PublishClientMqttMsgPublished(object sender, MqttMsgPublishedEventArgs e)
    {
        Log.Info("Message " + e.MessageId + " - published = " + e.IsPublished);
    }

    [ExportMethod]
    public void PublishMessage()
    {
        var variable1 = Project.Current.GetVariable("Model/Variable1");
        variable1.Value = new Random().Next(0, 101);

        // Publish a message
        ushort msgId = publishClient.Publish("/my_topic", // topic
            System.Text.Encoding.UTF8.GetBytes(((int)variable1.Value).ToString()), // message body
            MqttMsgBase.QOS_LEVEL_EXACTLY_ONCE, // QoS level
            false); // retained
    }

    private MqttClient publishClient;
}

Note: The code retrieves the value to publish from the Model > Variable1 variable that you will create later on.

Save the code.

Create the interface elements

In Project view, right-click Model and select New > Variable.

If needed, rename the variable to Variable1.

Variable1 is created. The variable value is retrieved by the PublisherLogic script.
Add the publish button by performing the following actions:
1. In Project view, right-click MainWindow (type) and select New > Base controls > Button.
2. Hover-over the button, select , and enter PublishButton.
3. In Properties, set Text to Publish
4. In Events, next to MouseClick event, select and select ProjectName > UI > MainWindow (type) > PublisherLogic > PublishMessage.