Develop Reference

TcpListener does not receive data

So my homework is to write a POP3 messaging software using tcp packets and im not allowed to use external libraries. I start the tcp connection when i press the Connect button and i also have a Disconnect button which stops it. I tested my server program with PuTTY and it works fine after the first connection but when i press Disconnect and Connect again it doesnt print the received data to the monitor. This problem is bothering me for ages please help. Here is my code:
Edit:
The problem was that i dont quite understand how threads work and i didnt create a new thread for each connection so i instantiated a new thread every time i created a new listener.
namespace POP3Server
{
public partial class MainWindow : Window
{
private TcpListener server;
private Int32 port;
private IPAddress ipAddress;
private TcpClient client;
private Logger log;
private Thread tcpAcceptThread;
private bool serverStarted;
public MainWindow()
{
InitializeComponent();
log = new Logger(txtConsole);
serverStarted = false;
tcpAcceptThread = new Thread(GetData);
}
private void btnConnect_Click(object sender, RoutedEventArgs e)
{
try
{
port = Convert.ToInt32(txtPort.Text);
ipAddress = IPAddress.Parse(txtIP.Text);
server = new TcpListener(ipAddress, port);
server.Start();
if (tcpAcceptThread.ThreadState != ThreadState.Unstarted)
tcpAcceptThread.Start();
serverStarted = true;
log.WriteLine("Server started!");
btnConnect.IsEnabled = false;
btnDisconnect.IsEnabled = true;
}
catch (Exception ex)
{
log.WriteLine(ex.ToString());
}
}
private void btnDisconnect_Click(object sender, RoutedEventArgs e)
{
try
{
if (client != null)
client.Close();
server.Stop();
log.WriteLine("Server stopped!");
serverStarted = false;
btnConnect.IsEnabled = true;
btnDisconnect.IsEnabled = false;
}
catch (Exception ex)
{
log.WriteLine(ex.ToString());
}
}
private void GetData()
{
try
{
while (serverStarted)
{
client = server.AcceptTcpClient();
this.Dispatcher.Invoke(() => log.WriteLine("Connected!"));
Byte[] bytes = new Byte[256];
String data = null;
NetworkStream stream = client.GetStream();
int i;
// Loop to receive all the data sent by the client.
while ((i = stream.Read(bytes, 0, bytes.Length)) != 0)
{
// Translate data bytes to a ASCII string.
data = System.Text.Encoding.ASCII.GetString(bytes, 0, i);
this.Dispatcher.Invoke(() => log.WriteLine("Received: " + data));
}
}
}
catch (Exception ex)
{
this.Dispatcher.Invoke(() => log.WriteLine(ex.ToString()));
}
}
private void btnClear_Click(object sender, RoutedEventArgs e)
{
log.Clear();
}
}
}

Could you change following code
private bool serverStarted;
to:
private object _someLockObject = new object();
private bool _serverStarted = false;
private bool serverStarted {
get {
lock (_someLockObject)
{
return _serverStarted;
}
}
set {
lock (_someLockObject)
{
_serverStarted = value;
}
}
};
My first hunch is boolean property is not updated.

Receiving continuous data using 32feet in .Net (BLUETOOTH)

I am creating a Windows Form application, where it is connecting to a device through bluetooth. I am able to send commands to the device and I am receiving the data continuously. The problem I am facing is that I am not able to show the continuous data in the text box. The text box only shows the first line of characters the application is receiving. Here is my code:
CONNECT BUTTON ACTION:
private void btnConnect_Click(object sender, EventArgs e)
{
if (listBox.SelectedItem != null)
{
lblProgress.Text = "";
btnStart.Enabled = true;
cBoxAvailablePorts.Enabled = cBoxAvailableBaudRates.Enabled = true;
try
{
int pos = listBox.SelectedIndex;
deviceInfo = array.ElementAt(pos);
if (pairDevice())
{
Thread thread = new Thread(() => connectThread());
thread.Start();
}
else
{
MessageBox.Show("Pair failed!");
}
}
catch (Exception ex)
{
MessageBox.Show(ex.ToString());
}
}
else
{
MessageBox.Show("Please connect to a device!");
}
}
THREAD ACTION
private void connectThread()
{
//BluetoothClient client = new BluetoothClient();
bc.BeginConnect(deviceInfo.DeviceAddress, serviceClass, this.connectCallBack, bc);
}
CALLBACK ACTION:
private void connectCallBack(IAsyncResult result)
{
//BluetoothClient client = (BluetoothClient)result.AsyncState;
try
{
if (bc.Connected)
{
MessageBox.Show("Connected!");
}
else
{
MessageBox.Show("Connection Failed!");
}
}
catch (Exception)
{
MessageBox.Show("Not able to identify Bluetooth devices! Please try again.!");
}
}
START BUTTON ACTION:
Here I send a command "S".
In button action I call sendMessage("S").
The function that is called is shown below:
public void sendMessage(string msg)
{
try
{
if (bc.Connected)
{
Stream stream = bc.GetStream();
stream.ReadTimeout = 1000;
StreamWriter streamWriter = new StreamWriter(stream);
streamWriter.WriteLine(msg);
streamWriter.Flush();
// Read operation
StreamReader streamReader = new StreamReader(stream);
string result = streamReader.ReadLine();
txtResult.Text = result;
}
else
{
MessageBox.Show("Sending failed!");
}
}
catch (Exception ex)
{
MessageBox.Show(ex.ToString());
}
}
I wrote the StreamReader part in a loop, and it gave me Socket Exception.
I also tried to get the data from Serial Port and used DataReceived event just in case, but still it didn't help.
Any help would be appreciated.
Thank you!

OKAY! I solved the problem. Without getting in trouble with 32feet library (though it is fun to code with 32feet), I thought to make communication through serial port. I connected the device with my laptop and got to know the outgoing COMPORT in bluetooth setting of my laptop. The two-way communication can only be done through outgoing COMPORT, not the incoming COMPORT.
Suppose the outgoing COMPORT is COM12 and the baud rate that I have set is 9600.
So here is my code:
public delegate void updateDelegate(string text);
private updateDelegate objDelegate;
private SerialPort serialPort;
public View() // constructor
{
InitializeComponent();
this.WindowState = FormWindowState.Normal;
this.StartPosition = FormStartPosition.CenterScreen;
this.objDelegate = new updateDelegate(getText);
serialPort = new SerialPort("COM12", 9600);
serialPort.Handshake = Handshake.None;
serialPort.Parity = Parity.None;
serialPort.StopBits = StopBits.One;
serialPort.DtrEnable = true;
serialPort.RtsEnable = true;
}
START BUTTON ACTION
private void btnStart_Click(object sender, EventArgs e)
{
sendData("S");
}
// SEND COMMAND
public void sendData(string msg)
{
try
{
if (!serialPort.IsOpen)
{
serialPort.Open();
//serialPort.Close();
}
if (serialPort.IsOpen)
{
serialPort.Write(msg);
}
}
catch (Exception ex)
{
MessageBox.Show(ex.ToString());
}
}
// READ DATA
public void readData()
{
try
{
serialPort.DataReceived += SerialPort_DataReceived;
}
catch (Exception ex)
{
MessageBox.Show(ex.ToString());
}
}
private void SerialPort_DataReceived(object sender, SerialDataReceivedEventArgs e)
{
string res = serialPort.ReadExisting();
Thread.Sleep(500);
txtResult.Invoke(this.objDelegate, new object[] {res});
}
public void getText(string text)
{
txtResult.Text = text;
}
I hope this will help someone! Thank you!!!

Interfacing Arduino with pc GUI using C#

I am just a beginner in c#. I am now trying to interface arduino with a GUI application. And i need a small function to automatically detect the port which I have connected Arduino. I tried using nested "try and catch" blocks but it failed. can anyone suggest a good way to automatic select the port in which arduino is connected and open that port such that we can move directly to coding other switches that do different functions in that arduino.

Recently i had the same situation and i wrote this method to check for our device, all you need to set your device to send specific Pattern on Specific input. In this example if you send 0x33 then your device have to send 0x8A to identify itself.
public enum SerialSignal
{
SendSync = 0x33,
ReceiveSync = 0x8A,
}
private static SerialPort _arduinoSerialPort ;
/// <summary>
/// Polls all serial port and check for our device connected or not
/// </summary>
/// <returns>True: if our device is connected</returns>
public static bool Initialize()
{
var serialPortNames = SerialPort.GetPortNames();
foreach (var serialPortName in serialPortNames)
{
try
{
_arduinoSerialPort = new SerialPort(serialPortName) { BaudRate = 9600 };
_arduinoSerialPort.Open();
_arduinoSerialPort.DiscardInBuffer();
_arduinoSerialPort.Write(new byte[] { (int)SerialSignal.SendSync }, 0, 1);
var readBuffer = new byte[1];
Thread.Sleep(500);
_arduinoSerialPort.ReadTimeout = 5000;
_arduinoSerialPort.WriteTimeout = 5000;
_arduinoSerialPort.Read(readBuffer, 0, 1);
// Check if it is our device or Not;
if (readBuffer[0] == (byte)SerialSignal.ReceiveSync){
return true;
}
}
catch (Exception ex)
{
Debug.WriteLine("Exception at Serial Port:" + serialPortName + Environment.NewLine +
"Additional Message: " + ex.Message);
}
// if the send Sync repply not received just release resourceses
if (_arduinoSerialPort != null) _arduinoSerialPort.Dispose();
}
return false;
}

public partial class Form1 : Form
{
SerialPort serial = new SerialPort();
static SerialPort cport;
public Form1()
{
InitializeComponent();
button1.Enabled = true;
button2.Enabled = false;
button3.Enabled = false;
}
private void button1_Click(object sender, EventArgs e)
{
int i;
try
{
string[] ports = SerialPort.GetPortNames();
foreach(string newport in ports)
{
cport = new SerialPort(newport, 9600);
cport.Open();
cport.WriteLine("A");
int intReturnASCII = serial.ReadByte();
char returnMessage = Convert.ToChar(intReturnASCII);
if (returnMessage == 'B')
{
button2.Enabled = true;
break;
}
else
{
cport.Close();
}
}
}
catch (Exception )
{
Console.WriteLine("No COM ports found");
}
}

I undertand that I'm a bit late, But I have created a simple and free C# NuGet library that allows for interaction between the host PC and an Arduino board!
Examples in the ReadMe.txt file.
ArduinoFace - NuGet

C# COM port not disposed

this is my first interaction here! I'm learning C# by myself, there will be a lot of errors beside to the bug i'm trying to get rid of, please be patient :)
I'm developing a very basic app that let you interact with serial ports, something like the tool integrated in Arduino.
There is a button that is meant to Connect/Disconnect, it lanches/stops a Backgroundworker that keeps the form updated with new data. I've tryed to move .close(); every where in the code, but nothing changed, when I try to open it again it catches the Exception. And other apps con't access too. I think that I simply don't know what I'm doing :)
Can you help me releasing the resource?
The code involved in this operation:
private void ConnectB_Click(object sender, EventArgs e)
{
if (!connected)
{
int baud = Convert.ToInt32(baudRate.SelectedItem.ToString());
COMport = new SerialPort(COMpick.SelectedItem.ToString(), baud, Parity.None, 8, StopBits.One);
try
{
COMport.Open();
connected = true;
ConnectB.Text = "Disconnect";
}
catch (ArgumentOutOfRangeException)
{
MessageBox.Show("Baud rate not valid.");
connected = false;
}
catch (ArgumentException)
{
MessageBox.Show("Port name not valid.");
connected = false;
}
catch (UnauthorizedAccessException)
{
MessageBox.Show("Access denied, try close applications that may using the port.");
connected = false;
}
if (backWorker.IsBusy != true)
{
backWorker.RunWorkerAsync();
}
}
else
{
connected = false;
backWorker.CancelAsync();
ConnectB.Text = "Connect";
}
}
private void backWorker_DoWork(object sender, DoWorkEventArgs e)
{
BackgroundWorker worker = sender as BackgroundWorker;
while (true)
{
if (worker.CancellationPending == true)
{
e.Cancel = true;
break;
}
else if(COMport.IsOpen)
{
// Get data and print it in the form
try
{
inbox = COMport.ReadLine() + '\n';
}
catch (InvalidOperationException) { }
//Scroll down the form, passing something useless to make it work
worker.ReportProgress(inbox.Length);
}
}
}
private void backWorker_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
this.COMport.Close();
this.COMport.Dispose();
}
Thank you!

Semaphore timing out while accessing a serial port?

I'm experiencing this problem while opening a serial port in C# (which should be dirt simple; or so I thought).
When I try to open a serial port, I am getting the following exception:
The semaphore time-out period has expired.‎
Here is the method that is doing this.
public static void Open_TheActivePortWeWillUse(String Drone_StringNameFromUser)
{
var TempSerialPort = new SerialPort (
Drone_StringNameFromUser,
(int) SerialPortParameter.TheSerialPortSpeed);
// Now we have a name that anybody can see and use
OurSpecificPorts.TheActivePortWeAreUsing = TempSerialPort;
// We'll do 8-N-1 since almost the whole planet does that
OurSpecificPorts.TheActivePortWeAreUsing.DataBits = 8;
// We'll do 8-N-1
OurSpecificPorts.TheActivePortWeAreUsing.Parity = Parity.None;
// We'll do 8-N-1
OurSpecificPorts.TheActivePortWeAreUsing.StopBits = StopBits.One;
OurSpecificPorts.TheActivePortWeAreUsing.DataReceived +=
OurBackGroundSerialPortReceiver;
// We can now open our active port, which is what this line does
OurSpecificPorts.TheActivePortWeAreUsing.Open();
}
The strangest thing for me is that I get this error inconsistently. Half the time it works okay, and the other half, it does not.
Does anybody see anything obviously wrong with my code? Am I missing something?

Declaring your SerialPort object inside the method will not allow access to it after the method closes. Here is a method that works to open the port:
private void OpenSerialPort(String portName)
{
try
{
serialPort1.Close();
serialPort1.PortName = portName;
serialPort1.BaudRate = 115200;
serialPort1.DataBits = 8;
serialPort1.Handshake = Handshake.None;
serialPort1.Parity = Parity.None;
serialPort1.RtsEnable = false;
serialPort1.StopBits = StopBits.One;
serialPort1.Open();
}
catch (Exception ex)
{
MessageBox.Show("Could not open serial port " + portName, "Error");
}
}
The SerialPort object is declared in the class:
namespace Arcadia
{
public partial class Form1 : Form
{
private SerialPort serialPort1;
And the callback is added in the constructor:
public Form1()
{
InitializeComponent();
serialPort1.DataReceived += new SerialDataReceivedEventHandler(this.SerialPortReadCallback);
Sending data is handled in a different method:
private void SerialPortWrite(String writeString)
{
if (serialPort1.IsOpen)
{
serialPort1.WriteLine(writeString);
}
}
And here is the received data callback:
private void SerialPortReadCallback(object sender, SerialDataReceivedEventArgs args)
{
try
{
while (serialPort1.BytesToRead > 0)
{
// Do something with the data
}
}
catch (Exception ex)
{
}
}