Hi,
I can't figure out how to get the event handler to work when data is received on the com port. I've looked around the forums here and I downloaded a console sample program that I tested on my computer and it works. But when I try and apply the same Idea to my C# windows form program I can't get the event to fire. Am I doing something wrong Some other post on the forum were talking about using different threads for the SerialDataReceivedEvent handler... Thanks in advance for your help.
Kevin Jones
using
System;using
System.Collections.Generic;using
System.ComponentModel;using
System.Data;using
System.Drawing;using
System.Text;using
System.Windows.Forms;using
System.IO.Ports;namespace
SerialEcho{
public partial class SerialEcho : Form
{
SerialPort txPort = new SerialPort();
SerialPort rxPort = new SerialPort();
public SerialEcho()
{
InitializeComponent();
startCom();
}
private void startCom()
{
SerialPort txPort = new SerialPort();
txPort.BaudRate = 19200;
txPort.DataBits = 8;
txPort.ReceivedBytesThreshold = 2;
txPort.StopBits = StopBits.One;
txPort.Parity = Parity.None;
txPort.DtrEnable = true;
txPort.Handshake = Handshake.RequestToSend;
txPort.DataReceived += new SerialDataReceivedEventHandler(txPort_DataReceived);
SerialPort rxPort = new SerialPort();
rxPort.BaudRate = 19200;
rxPort.DataBits = 8;
rxPort.StopBits = StopBits.One;
rxPort.Parity = Parity.None;
string[] ports = SerialPort.GetPortNames();
foreach (string port in ports)
{
txPortList.Items.Add(port);
rxPortList.Items.Add(port);
}
Console.WriteLine("The Following Serial Ports Were Found:");
// Display each port name to the Console
foreach (string port in ports)
{
Console.WriteLine(port);
}
Console.ReadLine();
}
private void txPort_DataReceived(object sender, EventArgs e)
{
byte[] txBuf;
Console.WriteLine("txPort_DataReceived:: Got new data from port!!");
txBuf = new byte[256];
txBuf[0] = (byte)txPort.ReadByte();
rxPort.Write(txBuf, 0, 1);
}
private void txConnectButton_Click(object sender, EventArgs e)
{
//Loop Back Testing function for the txPort
Console.WriteLine("txPortList.Text = " + txPortList.Text);
if ((txPortList.Text.Length != 0) && (!(txPort.IsOpen)))
{
txPort.PortName = txPortList.Text;
txPort.Open();
if (txPort.IsOpen)
{
txConnectButton.Text = "Disconnect";
}
}
else
{
txPort.Close();
txConnectButton.Text = "Connect";
}
}
private void rxConnectButton_Click(object sender, EventArgs e)
{
Console.WriteLine("rxListBox.Text = " + rxPortList.Text);
if ((rxPortList.Text.Length != 0) && (!(rxPort.IsOpen)))
{
rxPort.PortName = rxPortList.Text;
rxPort.Open();
rxConnectButton.Text = "Disconnect";
}
else
{
rxPort.Close();
rxConnectButton.Text = "Connect";
}
}
private void testButton_Click(object sender, EventArgs e)
{
txPort.WriteLine("ABCDEFG");
}
}
}
SerialPort SerialDataReceivedEventHandler
tjjang
As you use Handshake.RequestToSend.
Do you check that CtsHolding and RtsEnable is true before send
Have you checked DsrHolding and DtrEnable too
These are just checks for debugging.
YdN
Ok, I will try that and see if it works.
THanks,
KEvin
ozForever
Form the code that I had read, which actual Serial Port That You Do Mapped during runtime
txPort.PortName = txPortList.Text;
txPort.Open();
^ Continue to 'Open/Close' on "Various" Port
sorry if I do miss understand your logic here.
DenisM
Well In the startCom() method I enumerate all of the avaliable Com ports on the computer and place them in a textBoxList. This enables the user to select at runtime what com port he want's to use. You can open and close and change a port while the program is running. The testButton_Click method sends a some characters out of txPort and is hardwired for loopback testing. I can never get the characters that I send out to come back in the txPort_SerialDataReceived method. I think it has to do with something about threads... But I'm at a loss with this.
Thanks for your help so far!
Kevin
alvi fawad
It looks like you are attaching the event to the wrong port.
txPort.DataReceived += new SerialDataReceivedEventHandler(txPort_DataReceived);
Later you do
txPort.WriteLine("ABCDEFG");
Which sends data to rxPort, if I understand your program correctly. But there is no event on that port so no event will be triggerd.
Johnson Gao
Hi,
Should I try and create a seperate serial port class so that it can run in it's own thread
Kevin
Dan Kuehn
usmanm
The button event that sends the txPort.WriteLine("ABCDEFG") it is just a test function because I have the txPort connected to a loopback by external hardware. So the same data I send out I should get back in the SerialDataReceivedEventHandler.
Thanks,
Kevin
Jordi Valldaura Rique
Great you found it. I'll mark this thread as answered as it is solved.
Emerald
Hi,
Yeah both of those settings are true. I'm starting to think that it is not the way I have the port setup but the thread that the event handler is running in. There is a SerialPort console application example that I've compiled and it works. I'm using the sames settings except that I'm using the serial port in the form. How would I put start the event handler in different thread in a windows form application
Thanks,
Kevin
Paula Mestre
Have you checked that the hardware works
If you use HyperTerminal to send some testdata, is it echoed back
Tittle Joseph
Hi,
I found a working example of a Windows Forms application with a Serial Port. After staring hard at my code, you'll notice that I declare txPort = new SerialPort() twice. Same with the rxPort... There was some other things that I had to take out... Anyhow I wanted to say Thank You to you guys for your suggestions and willingness to help.
Have a Blessed Day,
Kevin