I have a magnetic card reader with serial port interface.
I used following C#.net code to send command to the card reader.
System.IO.Ports.SerialPort myport = new System.IO.Ports.Serialport("COM1", 9600, Parity.Nonek, 8, StopBits.One);
myport.Open();
// initiates the card reader to read.
myport.write("command to initiate card reader");
// Once the card is swiped it shows the read data.
MessageBox.Show(myport.ReadExisting());
myport.Close();
The above code will work well when i have some pause before Messagebox. But I don't want pause.Rather I want to initiate messagebox whenever the card is swiped.
How can we do so?
I am implementing this in user login system.
I assume you have some kind of GUI that you want to update on card swipe. I will assume you have a form with a single text box called "textBox1" and a button labelled "Start" (button1).
using System;
using System.Windows.Forms;
using System.IO;
using System.IO.Ports;
namespace SerialPortExample {
public partial class Form1 : Form {
SerialPort myport;
public Form1() {
InitializeComponent();
myport = new SerialPort("COM1", 9600, Parity.None, 8, StopBits.One);
myport.DataReceived += new SerialDataReceivedEventHandler(myport_DataReceived);
myport.ErrorReceived += new SerialErrorReceivedEventHandler(myport_ErrorReceived);
}
delegate void SerialDataReceivedDelegate(object sender, SerialDataReceivedEventArgs e);
delegate void SerialErrorReceivedDelegate(object sender, SerialErrorReceivedEventArgs e);
void myport_ErrorReceived(object sender, SerialErrorReceivedEventArgs e) {
if (this.InvokeRequired) {
this.Invoke(new SerialErrorReceivedDelegate(myport_ErrorReceived_Client), sender, e);
} else {
myport_ErrorReceived_Client(sender, e);
}
}
void myport_ErrorReceived_Client(object sender, SerialErrorReceivedEventArgs e) {
MessageBox.Show("Error recieved: " + e.EventType);
}
void myport_DataReceived(object sender, SerialDataReceivedEventArgs e) {
if (this.InvokeRequired) {
this.Invoke(new SerialDataReceivedDelegate(myport_DataRecieved_Client), sender, e);
} else {
myport_DataRecieved_Client(sender, e);
}
}
void myport_DataRecieved_Client(object sender, SerialDataReceivedEventArgs e) {
textBox1.Text = myport.ReadExisting();
}
private void button1_Click(object sender, EventArgs e) {
try {
if (myport.IsOpen) {
myport.Close();
button1.Text = "Start";
} else {
myport.Open();
button1.Text = "Stop";
}
} catch (IOException ex) {
MessageBox.Show(ex.Message);
}
}
}
}
I don't have a serial device to test this code on, but it should be correct.
Breaking it down, the important part is the method myport_DataRecieved. This method is called whenever data arrives on the serial port, i.e. when a card is swiped.
Other areas of interests are the Form1 constructor, where we initialize the SerialPort (but, not open it yet), and the method button1_Click where we open/close the port (and change the button's text to reflect that. We also handle exceptions, in case we can't open the port for some reason.
Edit: I've updated the answer, thanks to Hans's comment. You cannot directly access the UI controls from the data events, as they run on a different thread. I split the event methods in half, so that I could call Invoke on them, and run them in the proper context.
Related
I am working with arduino serial monitor. My goal is to connect through serial port, send some data and close the application after it's done.
This is a C# application. Everything works well besides the fact that the application does not close. To solve the issue, I added Application.Exit() call at the end of Form1_Load method. After this change, the application starts and closes without reading the uppercase letter that I'm sending.
Source code:
namespace ForTest
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void Form1_Load(object sender, EventArgs e)
{
string[] ports = SerialPort.GetPortNames();
foreach (string port in ports)
{
SerialPort sp = new SerialPort(port, 9600, Parity.None, 8, StopBits.One);
try
{
sp.Open();
try
{
sp.WriteLine("Z"); // Send 1 to Arduino
sp.Close();
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
}
catch (Exception ek)
{
System.Diagnostics.Debug.WriteLine(ek.Message);
}
}
Application.Exit();
}
private void label2_Click(object sender, EventArgs e)
{
}
private void label1_Click(object sender, EventArgs e)
{
}
}
}
if I understood properly, you want to send data FROM C# to ARDUINO and then you exit the C# app
you can't just call Application.exit() after the InitializeComponent(), instead to achieve that you need to exit after sending the data
sp.WriteLine("Z"); // Send 1 to Arduino
sp.Close();
Application.Exit(); ///here!!
I am trying to write a program that communicates with a controller. The controller is supposed to send a "welcome" message when a connection is successfully established and, in fact, it does when I connect using a communications software. However, using the .NET code below, I never see the welcome message. Beyond that, it works. How can I capture this message. It seems to be sent the moment the connection is established.
Again, I am able to communicate fine with the controller after connection but I simply cannot seem to get the welcome message that is sent a the moment the connection is opened.
using System;
using System.IO.Ports;
using System.Windows.Forms;
namespace WindowsFormsApplication1
{
public partial class Form1 : Form
{
public delegate void AddDataDelegate(String myString);
public AddDataDelegate myDelegate;
SerialPort sp;
public Form1()
{
InitializeComponent();
}
public void AddDataMethod(String myString)
{
richTextBox1.AppendText(myString);
richTextBox1.SelectionStart = richTextBox1.Text.Length;
richTextBox1.ScrollToCaret();
}
private void button1_Click(object sender, EventArgs e)
{
try
{
sp = new SerialPort(comboBox1.SelectedItem.ToString(),Int32.Parse(comboBox2.SelectedItem.ToString()));
sp.DataReceived += SerialPort_OnDataReceived;
sp.Close();
sp.Open();
richTextBox1.AppendText("open\n");
button2.Enabled = true;
button3.Enabled = true;
}
catch (Exception ex)
{
richTextBox1.AppendText(ex.Message);
}
}
void SerialPort_OnDataReceived(object sender,SerialDataReceivedEventArgs args)
{
SerialPort sp = sender as SerialPort;
string s = sp.ReadExisting();
richTextBox1.Invoke(this.myDelegate, new Object[] { s });
}
private void button2_Click(object sender, EventArgs e)
{
sp.WriteLine(textBox1.Text);
textBox1.Text = "";
}
private void button3_Click(object sender, EventArgs e)
{
sp.DiscardOutBuffer();
sp.DiscardInBuffer();
sp.Close();
richTextBox1.AppendText("\nclosed\n");
}
private void Form1_Load_1(object sender, EventArgs e)
{
this.myDelegate = new AddDataDelegate(AddDataMethod);
string[] Ports = SerialPort.GetPortNames();
comboBox2.SelectedIndex = comboBox2.Items.Count - 1;
Array.Sort(Ports, (a, b) => string.Compare(a.Substring(3).PadLeft(3, '0'), b.Substring(3).PadLeft(3, '0')));
foreach (string port in Ports)
{
comboBox1.Items.Add(port);
}
comboBox1.SelectedIndex = 0;
}
}
}
I worked it out. Required a slight delay between connection and trying to pull data from the port.
I currently have a program made using VB6 code that uses the MSCOMM control to pull back data from the serial port. This manages to successfully receive the data from my serial port, in which a Denso BHT-904B device is connected.
I am now trying to move this code over to C# so it fits in with a new piece of software that i am developing. To do this i am using the SerialPort class. However, the issue is that when i open the port up the data received event only fires when the device fails to communicate (which im guessing is due to a timeout). The data then received in the event is '↑↑↑↑↑'.
My SerialPort control settings are the following:
DtrEnable = True
PortName = COM3
ReadBufferSize = 1024
WriteBufferSize = 512
The code that i am using behind my form control is:
namespace BHTTestingDotNet
{
public partial class Form1 : Form
{
private string rxString;
public Form1()
{
InitializeComponent();
}
private void button1_Click(object sender, EventArgs e)
{
var serialPort = new SerialPort("COM3", 9600, Parity.None, 8, StopBits.One);
serialPort.DtrEnable = true;
serialPort.Encoding = Encoding.Default;
serialPort.DataReceived += serialPort_DataReceived;
serialPort.ErrorReceived += serialPort_ErrorReceived;
serialPort.Open();
}
private void serialPort_ErrorReceived(object sender, SerialErrorReceivedEventArgs e)
{
MessageBox.Show(e.ToString());
}
private void serialPort_DataReceived(object sender, System.IO.Ports.SerialDataReceivedEventArgs e)
{
var serialPort = (SerialPort)sender;
var test = serialPort.BytesToRead;
SerialPort sr = (SerialPort)sender;
rxString = sr.ReadExisting();
this.BeginInvoke(new EventHandler(displayText));
}
private void displayText(object o, EventArgs e)
{
txtBHT.AppendText(rxString);
}
}
}
I have already tried to set both RtsEnable and DtrEnable to true but that didn't make any difference.
UPDATE - I have now changed to protocol settings on the device but i now only receive pipes and then a return symbol, for example like so:
|||||¬
I am using SerialPort class often and for my purposes I have made my own class
public class SerialPortDataSource : SerialPort
where SerialPort.DataReceived handler invoke this method:
private void SerialPortDataSource_DataReceived(object sender, SerialDataReceivedEventArgs e)
{
try
{
if (BytesToRead > 0)
{
var buffor = new byte[BytesToRead];
Read(buffor, 0, buffor.Length);
_receivedBytes = buffor;
//wConsole.WriteLine(ArrayExtension.ToString(buffor));
var dataLogger = DataLogger;
if (dataLogger != null)
{
dataLogger.WriteLine("- DR - {0}", true, BitConverterExtension.ToHexString(buffor));
}
if (OnDataReceived != null)
{
OnDataReceived(this, buffor);
}
}
}
catch (InvalidOperationException)
{
// sometimes DataReceived event is invoked after port is closed which causes InvalidOperationException
}
}
This method is working for me in many applications with variety serial port settings.
I have a system that sends an "at" command to a serial port and displays the return on a MessageBox.
But I needed to do this in all available serial ports. So I created a List and I'm adding all the ports on it.
I managed to send the command, but could not continue the rest of the code to catch the return because I am having trouble handling the lists. I am a beginner in C #.
Below is my current code.
The part that is commented out is what I'm struggling to continue.
This part belongs to the old code (when it was just one serial port).
public partial class Form1 : Form
{
List<SerialPort> serialPort = new List<SerialPort>();
// delegate is used to write to a UI control from a non-UI thread
private delegate void SetTextDeleg(string text);
public Form1()
{
InitializeComponent();
}
private void Form1_Load(object sender, EventArgs e)
{
var portNames = SerialPort.GetPortNames();
foreach (var port in portNames) {
SerialPort sp;
sp = new SerialPort(port, 19200, Parity.None, 8, StopBits.One);
sp.Handshake = Handshake.None;
//sp.DataReceived += new SerialDataReceivedEventHandler(sp_DataReceived);
sp.ReadTimeout = 500;
sp.WriteTimeout = 500;
serialPort.Add(sp);
listPorts.Items.Add(port);
}
}
private void listPorts_SelectedIndexChanged(object sender, EventArgs e)
{
}
private void button1_Click(object sender, EventArgs e)
{
foreach (var sp in serialPort) {
// Open port
try
{
if (!sp.IsOpen)
sp.Open();
MessageBox.Show(sp.PortName + " aberto!");
sp.Write("at\r\n");
}
catch (Exception ex)
{
MessageBox.Show("Error opening/writing to serial port :: " + ex.Message, "Error!");
}
}
}
/* HELP START
void sp_DataReceived(object sender, SerialDataReceivedEventArgs e)
{
Thread.Sleep(500);
string data = sp.ReadLine();
this.BeginInvoke(new SetTextDeleg(si_DataReceived), new object[] { data });
}
private void si_DataReceived(string data)
{
String retorno = data.Trim();
MessageBox.Show(retorno);
// Fecha a porta após pegar o retorno
sp.Close();
}
HELP END */
}
What to put in place 'sp.ReadLine ();' and 'sp.Close ();'?
I don't know do this because of the List <>
The simplest approach would be to use a lambda expression which would capture the port you're using. A lambda expression is a way of building a delegate "inline" - and one which is able to use the local variables from the method you declare it in.
For example:
foreach (var port in portNames)
{
// Object initializer to simplify setting properties
SerialPort sp = new SerialPort(port, 19200, Parity.None, 8, StopBits.One)
{
Handshake = Hanshake.None,
ReadTimeout = 500,
WriteTimeout = 500
};
sp.DataReceived += (sender, args) =>
{
Thread.Sleep(500); // Not sure you need this...
string data = sp.ReadLine();
Action action = () => {
MessageBox.Show(data.Trim());
sp.Close();
};
BeginInvoke(action);
};
serialPort.Add(sp);
listPorts.Items.Add(port);
}
A few notes about this:
Just because some data has been received doesn't mean that a whole line has, so ReadLine may still block
If you only need to show a message box, you may not need Control.BeginInvoke. (If you need to do more here, you might want to extract most of that code into a separate method which just takes a string, then create an action which would call that method.)
Are you sure you want to close the serial port as soon as the first line has been received?
You can chage your sp_DataReceived method as,
void sp_DataReceived(object sender, SerialDataReceivedEventArgs e)
{
Thread.Sleep(500);
SerialPort sp = (SerialPort)sender;
string data = sp.ReadLine();
this.BeginInvoke(new SetTextDeleg(si_DataReceived), new object[] { data });
sp.Close();
}
and remove the sp.Close(); from si_DataReceived method.
If you want to have a Serial port value in your si_DataReceived method,
you should pass it there:
// First, add port into your delegate
private delegate void SetTextDeleg(SerialPort port, string text);
...
/* HELP START */
void sp_DataReceived(object sender, SerialDataReceivedEventArgs e)
{
Thread.Sleep(500);
SerialPort sp = (SerialPort) sender; // <- Obtain the serial port
string data = sp.ReadLine();
// Pass the serial port into si_DataReceived: SetTextDeleg(sp, ...
this.BeginInvoke(new SetTextDeleg(sp, si_DataReceived), new object[] { data });
}
// "SerialPort sp" is added
private void si_DataReceived(SerialPort sp, string data) {
String retorno = data.Trim();
MessageBox.Show(retorno);
// Fecha a porta após pegar o retorno
sp.Close();
}
/* HELP END */
See also:
http://msdn.microsoft.com/library/system.io.ports.serialport.datareceived.aspx
I'm trying to program the UBW in C# to take a command and give me the input back. For example, when I establish the USB connection in TeraTerm, a input v would give me a output of the current firmware version of the UBW I'm using.
I have the connection established in C#. I think I'm sending the command right, but my datareceived handler is never called in the debugger.
Here is the code to try to write to the port:
private void button1_Click(object sender, EventArgs e)
{
if (port.IsOpen)
{
//write command to port
port.WriteLine(textBox1.Text);
}
else
{
MessageBox.Show("Serial port is closed! Try again!");
}
textBox1.Clear();
}
Here is the code to try to read from it (which is never called from the debugger)
private void port_dataReceived(object sender, SerialDataReceivedEventArgs e)
{
try
{
port.ReadLine();
}
catch { }
}
Here is the UBW home page to show how it works. http://schmalzhaus.com/UBW/
My comboBox code to set up my port:
private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
{
string portName = comboBox1.SelectedItem.ToString();
port = new SerialPort(portName, 9600, Parity.None, 8, StopBits.One);
port.DataReceived += new SerialDataReceivedEventHandler(port_dataReceived);
try
{
port.Open();
//port.DataReceived += new SerialDataReceivedEventHandler(port_dataReceived);
}
catch
{
MessageBox.Show("The selected serial port cannot be opened!");
Application.Exit();
}
}
Go into TeraTerm's COM port properties, and make sure you're using the same properties in your code.
Try using this class (it wraps up a lot of serial stuff to make it easier):
http://code.google.com/p/flux3gui/source/browse/Flux3GUI/SerialCommunication.cs?r=b4a4f8546b936eeabe60b7de32e3027493498dc6