Using WebSockets Exception thrown: 'System.Net.WebSockets.WebSocketException' in System.Private.CoreLib.dll

[solrac3f]

Description

Using the following code in a .NET Form app. A Websocket connection to a Server is established and the commands are send correctly and received correctly on the server side.

Using the same code in a .NET MAUI app a Exception Error is thrown: 'System.Net.WebSockets.WebSocketException' in System.Private.CoreLib.dll

        private async void BtnOn_Clicked(object sender, EventArgs e)
        {
            await SendCommand("O");
        }

        private async void BtnOff_Clicked(object sender, EventArgs e)
        {
            await SendCommand("F");
        }

        private async Task SendCommand(string command)
        {
            ClientWebSocket socket = new ClientWebSocket();

            try
            {
                await socket.ConnectAsync(new Uri("ws://192.168.0.2:80/command"), CancellationToken.None);

                byte[] buffer = Encoding.UTF8.GetBytes(command);
                await socket.SendAsync(new ArraySegment<byte>(buffer), WebSocketMessageType.Text, true, CancellationToken.None);

                Trace.WriteLine("Incoming message: " + command);

                // Receive response if needed
                var responseBuffer = new byte[1024];
                var response = await socket.ReceiveAsync(new ArraySegment<byte>(responseBuffer), CancellationToken.None);
                var responseMessage = Encoding.UTF8.GetString(responseBuffer, 0, response.Count);

            }
            catch (Exception ex)
            {
                await DisplayAlert("Error", $"Error: {ex.Message}", "OK");
            }
            finally
            {
                if (socket.State == WebSocketState.Open || socket.State == WebSocketState.Connecting)
                    await socket.CloseAsync(WebSocketCloseStatus.NormalClosure, "Closed by the client", CancellationToken.None);

                socket.Dispose();
            }
        }

Steps to Reproduce

No response

Link to public reproduction project repository

No response

Version with bug

8.0.7 SR2

Is this a regression from previous behavior?

Not sure, did not test other versions

Last version that worked well

Unknown/Other

Affected platforms

Windows

Affected platform versions

No response

Did you find any workaround?

No response

Relevant log output

No response

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[jfversluis]

Hey there, thanks for the report!

I kinda doubt this is specific to .NET MAUI to be honest. If you create a WinUI app (without MAUI) does it work then? Would you be able to try that and verify?

You mention it does work for a WinForms app?

[solrac3f]

Yes, with WinForms app it works. I will try a WinUI app (without MAUI).

[jfversluis]

Please let us know the result!

That WinForms app does that run on the same .NET version? .NET 8? Or is that still .NET Framework? Can you maybe provide some more version information?

[solrac3f]

Yes the WinForms app runs on .NET 8. I created a WinUI app without MAUI. Like in the WinForms app it is working. The app runs on a Windows 10 Machine

Follows the code for the WinUI app:

using System;
using System.Diagnostics;
using System.Net.WebSockets;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;

// The Blank Page item template is documented at https://go.microsoft.com/fwlink/?LinkId=402352&clcid=0x409

namespace App2
{
    /// <summary>
    /// An empty page that can be used on its own or navigated to within a Frame.
    /// </summary>
    public sealed partial class MainPage : Page
    {
        public MainPage()
        {
            this.InitializeComponent();
        }

        private async void Button_Click(object sender, RoutedEventArgs e)
        {
            await SendCommand("O");
        }

        private async void Button_Click_1(object sender, RoutedEventArgs e)
        {
            await SendCommand("F");
        }

        private async Task SendCommand(string command)
        {
            ClientWebSocket socket = new ClientWebSocket();

            try
            {
                await socket.ConnectAsync(new Uri("ws://192.168.0.2:80/command"), CancellationToken.None);

                byte[] buffer = Encoding.UTF8.GetBytes(command);
                await socket.SendAsync(new ArraySegment<byte>(buffer), WebSocketMessageType.Text, true, CancellationToken.None);

                Trace.WriteLine("Incoming message: " + command);

                // Receive response if needed
                var responseBuffer = new byte[1024];
                var response = await socket.ReceiveAsync(new ArraySegment<byte>(responseBuffer), CancellationToken.None);
                var responseMessage = Encoding.UTF8.GetString(responseBuffer, 0, response.Count);

            }
            catch (Exception ex)
            {

                Console.WriteLine("Error", $"Error: {ex.Message}", "OK");
            }
            finally
            {
                if (socket.State == WebSocketState.Open || socket.State == WebSocketState.Connecting)
                    await socket.CloseAsync(WebSocketCloseStatus.NormalClosure, "Closed by the client", CancellationToken.None);

                socket.Dispose();
            }
        }
    }
}

[Eilon]

@solrac3f can you share the full stack trace of the exception?

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