.Net- Action<T> Delegate error? - c#

i am using Action<T> Delegate to make a link between class and Form. the class connects to serial port and data received is displayed in the form. the Action<T> Delegate encapsulates a method in the Form that displays the data received. but the delegate is always showing null, does not encapsulate the method.
the class code is :
public SerialPort mySerialPort;
public Action<byte[]> DataReceived_Del; //delegate for data recieved
public string connect()
{
try
{
mySerialPort = new SerialPort("COM14");
mySerialPort.BaudRate = 115200;
mySerialPort.DataBits = 8;
mySerialPort.Parity = System.IO.Ports.Parity.None;
mySerialPort.StopBits = System.IO.Ports.StopBits.One;
mySerialPort.RtsEnable = false;
mySerialPort.DataReceived += mySerialPort_DataReceived;
mySerialPort.Open();
}
catch (SystemException ex)
{
MessageBox.Show(ex.Message);
}
if (mySerialPort.IsOpen)
{
return "Connected";
}
else
{
return "Disconnected";
}
}
//serial port data recieved handler
public void mySerialPort_DataReceived(object sender, SerialDataReceivedEventArgs e)
{
try
{
//no. of data at the port
int ByteToRead = mySerialPort.BytesToRead;
//create array to store buffer data
byte[] inputData = new byte[ByteToRead];
//read the data and store
mySerialPort.Read(inputData, 0, ByteToRead);
var copy = DataReceived_Del;
if (copy != null) copy(inputData);
}
catch (SystemException ex)
{
MessageBox.Show(ex.Message, "Data Received Event");
}
}
in the form we display the data:
public Form1()
{
InitializeComponent();
Processes newprocess = new Processes();
newprocess.DataReceived_Del += Display;
}
//Display
public void Display(byte[] inputData)
{
try
{
Invoke(new Action(() => TboxDisp.AppendText((BitConverter.ToString(inputData)))));
}
catch (SystemException ex)
{
MessageBox.Show(ex.Message, "Display section");
}
}
the DataReceived_Del supposed to encapsulate the method Display, but it is NULL.
I can't see what is happening..
Any help is appreciated..

you should define newprocess outside the constructor , may this will resolve the
Processes newprocess;
public Form1()
{
InitializeComponent();
newprocess = new Processes();
newprocess.DataReceived_Del += Display;
}

You are using += to add to the delegate, but the delegate is NULL to begin with. I'm not sure that will work. I would try = instead of +=.
public Form1() {
InitializeComponent();
Processes newprocess = new Processes();
newprocess.DataReceived_Del = Display;
}

Related

Reading Serial Data from Arduino in Windows Forms Application

I am currently trying to build a windows forms app that gets sensor data from an arduino via the serial com.
when checking in the arduino IDE the data gets writen into the serial port correctly.
But i can't figure out how to read the data via c#.
class Program
{
static SerialPort SP;
static void Main(string[] args)
{
SP = new SerialPort();
SP.PortName = "COM7";
SP.BaudRate = 9600;
SP.Handshake = System.IO.Ports.Handshake.RequestToSend;
SP.Open();
while (true)
{
Console.WriteLine(DateTime.Now.ToString() + " : " + SP.ReadLine());
}
}
}
My guess is that the Port is not properly set up, but i have no idea what i am missing.
The Goal is just to receive strings from the arduino, i do not necessarily need to send any data to the arduino.
edit: i am working with an arduino micro
Did you close Arduino IDE?
You need to add a wait code before reading from the port
Below is a working example:
private SerialPort _currentPort = new SerialPort("COM7", 9600);
private readonly object _sync = new object();
public bool Open()
{
_currentPort.Encoding = Encoding.UTF8;
_currentPort.DtrEnable = true;
_currentPort.ReadTimeout = 2000;
try
{
if (!_currentPort.IsOpen)
lock (_sync)
{
if (_currentPort.IsOpen)
return true;
_currentPort.Open();
System.Threading.Thread.Sleep(1500);
}
}
catch (Exception e)
{
//_localLogger?.Error($"{_currentPort.PortName}, {e.Message}", e);
return false;
}
return _currentPort.IsOpen;
}
public bool Subscribe()
{
try
{
if (Open())
{
_currentPort.DataReceived += CurrentPortOnDataReceived;
return true;
}
return false;
}
catch (Exception e)
{
//_localLogger?.Error($"{_currentPort.PortName}, {e.Message}", e);
return false;
}
}
private void CurrentPortOnDataReceived(object sender, SerialDataReceivedEventArgs e)
{
if (!_currentPort.IsOpen)
{
//_localLogger.Info($"{_currentPort} is closed");
Open();
}
Console.WriteLine(_currentPort.ReadExisting());
}

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!!!

Serial communication in c#

I have made a simple windows form with a ComboBox, TextBox and two Buttons to setup a serial protocol with my hardware.
However, whenever I send something I do get reply from hardware but C# doesn't display it. Instead it gives an exception saying that the operation has timed out. I even used an oscilloscope to check if I received something and it was positive. But C# doesn't display the code as stated before.
I am attaching my code below. Anyhelp would be welcome. Thanks in advance.
public partial class Form3 : Form
{
string buffer;
public SerialPort myComPort = new SerialPort();
delegate void setTextCallback(string text);
public Form3()
{
InitializeComponent();
}
private void Form3_Load(object sender, EventArgs e)
{
try
{
ManagementObjectSearcher searcher =
new ManagementObjectSearcher("root\\CIMV2",
"SELECT * FROM Win32_PnPEntity");
foreach (ManagementObject queryObj in searcher.Get())
{
if (queryObj["Caption"].ToString().Contains("(COM"))
{
comboBox1.Items.Add(queryObj["Caption"]);
}
}
comboBox1.Text = comboBox1.Items[0].ToString();
}
catch (ManagementException ex)
{
MessageBox.Show(ex.Message);
}
}
private void setText(string text)
{
if (textBox1.InvokeRequired)
{
setTextCallback tcb = new setTextCallback(setText);
this.Invoke(tcb, new object[] { text });
}
else
{
textBox1.Text = text;
}
}
void myComPort_DataReceived(object sender, SerialDataReceivedEventArgs e)
{
try
{
string myString = myComPort.ReadLine();
setText(myString);
}
catch (System.Exception ex)
{
MessageBox.Show(ex.Message, "Error", MessageBoxButtons.OK, MessageBoxIcon.Warning);
}
}
private void button1_Click(object sender, EventArgs e)
{
myComPort.Close();
// button1.Enabled = false;
string name = comboBox1.Text;
string[] words = name.Split('(', ')');
myComPort.PortName = words[1];
myComPort.ReadTimeout = 5000;
// myComPort.WriteTimeout = 500;
myComPort.BaudRate = 9600;
myComPort.DataBits = 8;
myComPort.StopBits = StopBits.One;
myComPort.Parity = Parity.None;
myComPort.DataReceived += new SerialDataReceivedEventHandler(myComPort_DataReceived);
myComPort.Open();
}
private void button2_Click(object sender, EventArgs e)
{
myComPort.WriteLine("?GV1\r");
}
}
It say
...The DataReceived event is not guaranteed to be raised for every byte received...
Try something like:
private static void DataReceived(object sender, SerialDataReceivedEventArgs e)
{
// prevent error with closed port to appears
if (!_port.IsOpen)
return;
// read data
if (_port.BytesToRead >= 1)
{
// ...
// read data into a buffer _port.ReadByte()
DataReceived(sender, e);
}
// ...
// if buffer contains data, process them
}
Have a look at this url:
http://csharp.simpleserial.com/
And this url for WMI:
http://www.codeproject.com/Articles/32330/A-Useful-WMI-Tool-How-To-Find-USB-to-Serial-Adapto

Why does C# thread die?

This is my 1st C# project so I may be doing something obviously improper in the code below.
I am using .NET, WinForms (I think), and this is a desktop application until I get the bugs out.
UpdateGui() uses Invoke((MethodInvoker)delegate to update various GUI controls based on received serial data and
sends a GetStatus() command out the serial port 4 times a second.
Thread Read() reads the response from serial port whenever it arrives which should be near immediate.
SerialPortFixer is a SerialPort IOException Workaround in C# I found at
http://zachsaw.blogspot.com/2010/07/serialport-ioexception-workaround-in-c.html.
After one or both threads die I'll see something like
The thread 0x1288 has exited with code 0 (0x0).
in the debug code output.
Why do UpdateGui() and/or Read() eventually die?
public partial class UpdateStatus : Form
{
private readonly byte[] Command = new byte[32];
private readonly byte[] Status = new byte[32];
readonly Thread readThread;
private static readonly Mutex commandMutex = new Mutex();
private static readonly Mutex statusMutex = new Mutex();
...
public UpdateStatus()
{
InitializeComponent();
SerialPortFixer.Execute("COM2");
if (serialPort1.IsOpen)
{
serialPort1.Close();
}
try
{
serialPort1.Open();
}
catch (Exception e)
{
labelWarning.Text = LOST_COMMUNICATIONS + e;
labelStatus.Text = LOST_COMMUNICATIONS + e;
labelWarning.Visible = true;
}
readThread = new Thread(Read);
readThread.Start();
new Timer(UpdateGui, null, 0, 250);
}
static void ProcessStatus(byte[] status)
{
Status.State = (State) status[4];
Status.Speed = status[6]; // MSB
Status.Speed *= 256;
Status.Speed += status[5];
var Speed = Status.Speed/GEAR_RATIO;
Status.Speed = (int) Speed;
...
}
public void Read()
{
while (serialPort1 != null)
{
try
{
serialPort1.Read(Status, 0, 1);
if (Status[0] != StartCharacter[0]) continue;
serialPort1.Read(Status, 1, 1);
if (Status[1] != StartCharacter[1]) continue;
serialPort1.Read(Status, 2, 1);
if (Status[2] != (int)Command.GetStatus) continue;
serialPort1.Read(Status, 3, 1);
...
statusMutex.WaitOne();
ProcessStatus(Status);
Status.update = true;
statusMutex.ReleaseMutex();
}
catch (Exception e)
{
Console.WriteLine(#"ERROR! Read() " + e);
}
}
}
public void GetStatus()
{
const int parameterLength = 0; // For GetStatus
statusMutex.WaitOne();
Status.update = false;
statusMutex.ReleaseMutex();
commandMutex.WaitOne();
if (!SendCommand(Command.GetStatus, parameterLength))
{
Console.WriteLine(#"ERROR! SendCommand(GetStatus)");
}
commandMutex.ReleaseMutex();
}
private void UpdateGui(object x)
{
try
{
Invoke((MethodInvoker)delegate
{
Text = DateTime.Now.ToLongTimeString();
statusMutex.WaitOne();
if (Status.update)
{
if (Status.Speed > progressBarSpeed.Maximum)
{
Status.Speed = progressBarSpeed.Maximum;
}
progressBarSpeed.Value = Status.Speed;
labelSpeed.Text = Status.Speed + RPM;
...
}
else
{
labelWarning.Text = LOST_COMMUNICATIONS;
labelStatus.Text = LOST_COMMUNICATIONS;
labelWarning.Visible = true;
}
statusMutex.ReleaseMutex();
GetStatus();
});
}
catch (Exception e)
{
Console.WriteLine(#"ERROR! UpdateGui() " + e);
}
}
}
A thread will terminate when there's no more code to execute, or more specifically when the method you specify when you create thread returns.
Maybe serialport1 becomes null?
As for the update timer, there is a special purpose windows forms timer that runs periodically that doesn't require you to use Invoke. It's the right tool for the job

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