Receiving message from Service Bus queue is working on console apps but not in windows form apps?

Question

I have the following c# functions that allow me to receive messages from a given queue from Azure, it works fine on console apps :

public  async Task MainReceiver()
        {
            queueClient = new QueueClient(connectionString, queueName);

            var messageHandlerOptions = new MessageHandlerOptions(ExceptionReceivedHandler)
            {
                MaxConcurrentCalls = 5,
                AutoComplete = false,

            };

            queueClient.RegisterMessageHandler(ProcessMessagesAsync, messageHandlerOptions);

            Console.ReadLine();

            await queueClient.CloseAsync();
        }

        public  async Task ProcessMessagesAsync(Message message, CancellationToken token)
        {
            var jsonString = Encoding.UTF8.GetString(message.Body);
            Console.WriteLine($"Person Received: { jsonString }");
            List<string> data = new List<string>();

            if (messageLists.ContainsKey(queueName))
            {
                data = messageLists[queueName];
                messageLists.Remove(queueName);
                data.Add(jsonString);
            }
            else
            {
                data.Add(jsonString);
            }
            messageLists.Add(queueName, data);

            await queueClient.CompleteAsync(message.SystemProperties.LockToken);
        }

My goal now is to list the messages using a listbox control. But if i try to call the same main methode in a button click, nothing happends, in debug mode i noticed that my breakpoint in ProcessMessagesAsync is never reached by my win form app.

public async void button2_Click(object sender, EventArgs e)
        {
            await receiveMessage();
        }
public async Task receiveMessage()
        {
            await messages.MainReceiver();
            List<string> data = new List<string>();
            data = messages.messageLists["eventsqueue"];
            for (int i = 0; i < messages.messageLists.Count; i++)
                listBox1.Items.Add(data[i]);
        }

I tried to use to queue my task in the thread pool using the following code , but it didn't help :

ThreadPool.QueueUserWorkItem(async (w) => await messages.MainReceiver());

Answer 1

Please follow the below workaround to achieve Service Bus queue messages into Windows Forms

Three major steps to show your data into LISTBOX

1. Create a list box using the ListBox() constructor is provided by the ListBox class.

    ListBox listBox1 = new ListBox();
   

2. Set/Add the Items property of the ListBox provided by the ListBox class.

    listBox1.Items.Add("your data to add in listbox");
   

3. Add this ListBox control to the form using Add() method.

    this.Controls.Add(listBox1);
   

Here I am following the above steps.

Program.cs

    using System.Collections.Generic;
    using System.Windows.Forms;
    
    namespace servicebuswinform
    {
        using Microsoft.Azure.ServiceBus;
        using System;
        using System.Text;
        using System.Threading;
        using System.Threading.Tasks;
        public class Program
        {
            const string ServiceBusConnectionString = <ServiceBus Connection string>;
            const string QueueName = "<Queue name>";
            static IQueueClient queueClient;
            public static List<string> data = new List<string>();
    
            [STAThread]
        
            public static void Main()
            {
                Application.SetHighDpiMode(HighDpiMode.SystemAware);
                Application.EnableVisualStyles();
                Application.SetCompatibleTextRenderingDefault(false);
                Application.Run(new Form1());
            }
        
            public static async Task MainAsync()
            {
                const int numberOfMessages = 10;
                queueClient = new QueueClient(ServiceBusConnectionString, QueueName);
                RegisterOnMessageHandlerAndReceiveMessages();
                // Send Messages
                await SendMessagesAsync(numberOfMessages);
                await queueClient.CloseAsync();
            }
        
            public static void RegisterOnMessageHandlerAndReceiveMessages()
            {
                var messageHandlerOptions = new MessageHandlerOptions(ExceptionReceivedHandler)
                {
                    MaxConcurrentCalls = 1,
                    AutoComplete = false
                };
                // Register the function that will process messages
                queueClient.RegisterMessageHandler(ProcessMessagesAsync, messageHandlerOptions);
            }
        
            public static async Task ProcessMessagesAsync(Message message, CancellationToken token)
            {
                //Adding message into list
                data.Add("Received message: SequenceNumber:"+ message.SystemProperties.SequenceNumber.ToString()+" Body:" + Encoding.UTF8.GetString(message.Body));
                await queueClient.CompleteAsync(message.SystemProperties.LockToken);
            }
        
        // Use this Handler to look at the exceptions received on the MessagePump
        
            public static Task ExceptionReceivedHandler(ExceptionReceivedEventArgs exceptionReceivedEventArgs)
            {
                Console.WriteLine($"Message handler encountered an exception {exceptionReceivedEventArgs.Exception}.");
                var context = exceptionReceivedEventArgs.ExceptionReceivedContext;
                Console.WriteLine("Exception context for troubleshooting:");
                Console.WriteLine($"- Endpoint: {context.Endpoint}");
                Console.WriteLine($"- Entity Path: {context.EntityPath}");
                Console.WriteLine($"- Executing Action: {context.Action}");
                return Task.CompletedTask;
            }
    
            public static async Task SendMessagesAsync(int numberOfMessagesToSend)
            {
                try
                {
                for (var i = 0; i < numberOfMessagesToSend; i++)
                    {
                        // Create a new message to send to the queue
                        string messageBody = $"Message {i}";
                        var message = new Message(Encoding.UTF8.GetBytes(messageBody));
                        // Write the body of the message to the console
                        Console.WriteLine($"Sending message: {messageBody}");
                        // Send the message to the queue
                        await queueClient.SendAsync(message);
                    }
                }
                catch (Exception exception)
                {
                    Console.WriteLine($"{DateTime.Now} :: Exception: {exception.Message}");
                }
            }
        }
    }

Form.cs

Here I am adding one button if we hit the button it will get the service bus queue messages and it will be added in Listbox.

    using System;
    using System.Collections.Generic;
    using System.Threading.Tasks;
    using System.Windows.Forms;
    namespace servicebuswinform
    {
        public partial class Form1 : Form
        {
            public static List<string> data1 = new List<string>();
            public Form1()
            {
                InitializeComponent();
            }
            
            public async void button1_Click(object sender, EventArgs e)
            {
                await receiveMessage();
                ListBox listBox1 = new ListBox();
                this.listBox1.Visible = true;
                for (int i = 0; i < data1.Count; i++)
                {
                    listBox1.FormattingEnabled = true;
                    listBox1.Enabled = true;
                    listBox1.Size = new System.Drawing.Size(692, 214);
                    listBox1.Location = new System.Drawing.Point(1, 131);
                    listBox1.MultiColumn = true;
                    listBox1.SelectionMode = SelectionMode.MultiExtended;
                    listBox1.BeginUpdate();
                    listBox1.Items.Add("item" + data1[i].ToString());
                }
                this.Controls.Add(listBox1);
            }
            
            public static async Task receiveMessage()
            {
                await Program.MainAsync();
                data1 = Program.data;
            }
            private void Form1_Load(object sender, EventArgs e)
            {
                this.listBox1.Visible = false;
            }
        }
    }

You can follow the above steps which I have mentioned. Using this I can see the list of service bus queue messages in windows forms