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serial port myPort.Datareceived C#

Hello friends have a form in C # that reads data from a serial device connected, my problem is that I even changing form of the method myPort.DataReceived still running and receiving data. There's no way I close the connection with the serial port because the method does not stop excutar. I've tried a command to zip it when I change my form but it crashes when you try to run the myPort.Close, I believe that is why the myPort.DataReceived still running, so I removed the code and it continues myPort.Close open in another form. I think my solution would be to stop the myPort.DataReceived to then close connection, but can not find way to do this.Below is an excerpt from my code:
namespace EntradaFinalCliente
{
public partial class ConsultaSerial : Form
{
string SerialString;
private SerialPort myport;
public ConsultaSerial()
{
InitializeComponent();
abrirSerial();
lerDados();
}
public void abrirSerial()
{
myport = new SerialPort();
myport.BaudRate = 9600;
myport.PortName = SerialPort1;
myport.DataReceived += myport_DataReceived;
}
private void lerDados()
{
if (myport.IsOpen == false)
{
try
{
myport.Open();
}
catch
{
return;
}
}
}
private void myport_DataReceived(object sender, SerialDataReceivedEventArgs e)
{
Thread.Sleep(100);
SerialString = myport.ReadExisting();
this.Invoke(new EventHandler(Analisa));
}
private void Analisa(object sender, EventArgs e)
{
checarSerial();
}
And this is my closing the form button:
private void button1_Click (object sender, EventArgs e)
{
myPort.Close ();
this.Hide ();
var form1 = new Form1 ();
form1.Closed + = (s, args) => this.Close ();
Form1.Show ();
}

The issue you have it that once the event has been triggered, your application would have entered the function myport_DataReceived. The function will continue to execute regardless of whether the port has been closed. If the port has been closed, the function would execute for the last time. Waiting for 100ms makes it worse. So my advice is to remove the wait and put a try catch statement around the code to make the thread terminate cleanly.
Furthermore, it is better if you use the sender to read the incoming data than using the member myPort because the sender is the one that fires the event. It also helps to remove confusion when you open two or more ports.
It is also advised that the body of DataReceived event handler function should be kept to minimum. Only do what you need to get the data out. You can then store the data in memory and do more complicated handling somewhere else using the stored data.
private void myport_DataReceived(object sender, SerialDataReceivedEventArgs e)
{
Thread.Sleep(100); // Why do you need to wait for 100 ms? If the event reaches here, it will have the data to read. Can remove?
try
{
SerialPort sp = (SerialPort)sender;
SerialString = sp.ReadExisting();
this.Invoke(new EventHandler(Analisa));
}
catch (Exception ex)
{
// Do something else
Console.WriteLine(ex.Message);
}
}

Serial port auto close hangs

I'm trying to open and close a serial port with one button click event. But it always hangs whenever it hits the serialport.close part. Why?
private void btn_auto_Click(object sender, EventArgs e)
{
try
{
myport = new SerialPort();
myport.BaudRate = 9600;
myport.PortName = cb_portname.Text;
myport.Open();
myport.DataReceived += new SerialDataReceivedEventHandler(myport_DataReceived2);
}
catch (Exception ex)
{
MessageBox.Show(ex.Message, "Error");
}
}
}
void myport_DataReceived2(object sender, SerialDataReceivedEventArgs e)
{
try
{
in_data = myport.ReadLine();
this.Invoke(new EventHandler(displaydata_event2));
}
catch (Exception)
{
}
}
private void displaydata_event2(object sender, EventArgs e)
{
string inStr;
inStr = in_data;
if (inStr.Length == 18)
{
int indexOfSpace = inStr.IndexOf(':');
string Temp = inStr.Substring(indexOfSpace + 1);
txtData2.Text = Temp;
}
if (txtData2.Text != "")
{
myport.Close(); //===== ALWAYS HANGS AT THIS PART =====
MessageBox.Show("STOPPED");
}
}
So, it always hangs under the if txtData2 not equals part.
Is it due to it requires a button action for a serialport to close and it cannot auto close? Thanks in advance.

Looking at the source code for the SerialPort class, and in particular for its associated SerialStream class, it appears that the Close() method will block waiting for handlers of any raised events to complete.
Your handling of the received data seems a bit suspect in any case, in that you only even bother to look at the received data if the received line is exactly 18 characters long, as well as in that you are using an instance field to pass data between two methods (very bad idea).
But most likely the biggest issue here, the one causing the deadlock, is that you are calling the SerialPort.Close() method before the DataReceived event handler has completed. Don't do that. Fix your code so that handling received data is a completely independent operation from actually closing the serial port, so that the former can complete before you attempt the latter.

Serial Port does not receive whole data in C#

I am using C# serial port controlling gsm modem. Now in Mikroelectronia USART Terminal
after sending:
AT+CUSD=1,"*778#",15
It receives:
AT+CUSD=1,"*778#",15
OK
+CUSD: 0,"Balance: 0.00 TK. Validity: 29-Jul-13. Bonus: 0.00TK. Free Min: 0. Dial *121*2092# for 3 hit songs of Ashiqui-2 as ur Caller
Tunetk.10",64
But in C# after sending data
AT+CUSD=1,"*778#",15
it returns:
AT+CUSD=1,"*778#",15
OK
+CUSD: 0,"Balance: 0.00 TK. Validity: 29-Jul-13. Bonus: 0.00TK. Free Min: 0. Dial *121*2092# for 3 hit songs of Ashiqui-2 as ur Caller Tune
That means in C# it does not receive any data after "Caller Tune". Why is that happening? Part of C# code I have used is
private void Form1_Load(object sender, EventArgs e)
{
sp1.DataReceived += new SerialDataReceivedEventHandler(sp_DataReceived);
}
void sp_DataReceived(object sender, SerialDataReceivedEventArgs e)
{
var valueOfPort = sp1.ReadExisting();
textBox1.AppendText(valueOfPort);
}
private void button1_Click(object sender, EventArgs e)
{
TextBox.CheckForIllegalCrossThreadCalls = false;
try
{
if (!sp1.IsOpen)
{
sp1.Open();
}
sp1.Write(textBox2.Text+"\r");
}
catch(Exception ex)
{
MessageBox.Show(string.Format("Exception : {0}", ex.Message), "Port Error");
}
}

the TextBox.CheckForIllegalCrossThreadCalls = false; makes me very suspicious, I think that is what is breaking your program, simply just invoke to update the text box properly and I think it will work. Just change the event code to the following:
void sp_DataReceived(object sender, SerialDataReceivedEventArgs e)
{
if(textbox1.InvokeRequired)
{
textbox1.Invoke(new SerialDataReceivedEventHandler(sp_DataReceived), sender, e);
}
else
{
var valueOfPort = sp1.ReadExisting();
textBox1.AppendText(valueOfPort);
}
}
What this will do is check if you are running on the correct thread, if not it restarts the function again on the UI thread with the same arguments. Also be sure to remove the TextBox.CheckForIllegalCrossThreadCalls = false;
UPDATE: After re-reading the MSDN I found this remark
This method returns the contents of the stream and internal buffer of the SerialPort object as a string. This method does not use a time-out. Note that this method can leave trailing lead bytes in the internal buffer, which makes the BytesToRead value greater than zero.
Try checking to see if there is more data to read after calling ReadExisting.
void sp_DataReceived(object sender, SerialDataReceivedEventArgs e)
{
if(textbox1.InvokeRequired)
{
textbox1.Invoke(new SerialDataReceivedEventHandler(sp_DataReceived), sender, e);
}
else
{
while(sp1.BytesToRead > 0)
{
var valueOfPort = sp1.ReadExisting();
textBox1.AppendText(valueOfPort);
}
}
}

Have you defined your device's EOL and set it correctly in your program?
C# serial port does not necessarily fire up DataReceive at the start of the message nor does it know where the message ends. It may terminate anywhere in the message. You should try explicitly set the EOL which can be uniquely identified by the port in order for it to buffer incoming message and to return it once it is completed.
// e.g. I normally used (carriage return + newline) instead of just either one
sp1.NewLine = "\r\n";

MessageBox.Show called from backgound worker with the handle of the main UI thread

I have this code:
public void Blah(IWin32Window _this)
{
for (int i = 0; i < item_quantity; i++)
{
try { File.Delete(item[0, i]); }
catch (Exception ex)
{
if (MessageBox.Show(_this, String.Format("Error while accessing {0}\n{1}"
, item[0, i], ex.Message), "Error", MessageBoxButtons.RetryCancel
, MessageBoxIcon.Error) == DialogResult.Retry)
{ i--; }
}
}
}
...and this code in the main UI thread:
private void backgroundWorker_DoWork(object sender, DoWorkEventArgs e)
{
AnotherClass.Blah(this);
}
When I execute this code, I get the unsafe cross-thread exception. What's the safe way to do this operation?

What's the safe way to do this operation?
There is no real safe way to do this. The message box pops out of nowhere, without any direct connection to a command that the user gave. One failure mode is that the user continues working with your UI, clicking the mouse or pressing the space bar. And your message box pops up a millisecond before he clicked the mouse or pressed a key. He'll never see the message.
So something was supposed to be done, it didn't get done and the user is completely unaware of it. Not a good thing. You'll need to doctor your UI so this condition can never occur. Clearly that will require that you do error reporting a different way than by using a temporary message box. Many possible alternatives of course, could be as simple as a Label that reports state. StatusStrip is good for this.
The actual exception is a bogus one. It is triggered by the built-in diagnostics that checks that code uses UI in a thread-safe way. The underlying winapi call is GetParent(), one of the very few user32 Windows functions that can safely be called, and used, from a worker thread. The only legitimate reason I know where using Control.CheckForIllegalCrossThreadCalls to work around the problem is okay. But fix the real problem instead.

I'm not condoning the design, but you can pass in the Form to Blah() and then Invoke() against the referenced form:
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void button1_Click(object sender, EventArgs e)
{
if (!backgroundWorker.IsBusy)
{
button1.Enabled = false;
backgroundWorker.RunWorkerAsync();
}
}
private void backgroundWorker_DoWork(object sender, DoWorkEventArgs e)
{
SomeClass AnotherClass = new SomeClass();
AnotherClass.Blah(this);
}
private void backgroundWorker_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
button1.Enabled = true;
MessageBox.Show("Done!");
}
}
public class SomeClass
{
public void Blah(Form frm)
{
int item_quantity = 5;
for (int i = 0; i < item_quantity; i++)
{
try
{
//File.Delete(item[0, i]);
Console.WriteLine("i = " + i.ToString());
throw new Exception("duh");
}
catch (Exception ex)
{
frm.Invoke(new Action(() =>
{
DialogResult result = MessageBox.Show(frm, String.Format("Error while accessing {0}\n{1}", "something", ex.Message), "Error", MessageBoxButtons.RetryCancel, MessageBoxIcon.Error);
if (result == DialogResult.Retry)
{
i--;
}
}));
}
}
}
}

You are trying to do UI work on a background thread, hence the cross-thread exception. RunWorkerCompletedEventArgs has a property called Error that will hold any exception that gets thrown by the RunWorkerAsync delegate. Set up a handler for RunWorkerCompleted on your BackgroundWorker and check if the Error property has a value. If it does, prompt the MessageBox in the handler because you will be on the UI thread at that point. Call the BackgroundWorker's RunWorkerAsync method again on the DialogResult.Retry scenario.
(You will probably have to tweak your BackgroundWorker and AnotherClass.Blah to take in the value of i to prime your loop condition for that second call to your BackgroundWorker. The DoWorkEventArgs has a property called Argument that you can use to pass in that value.)

You need to execute UI code like this when calling it from another thread:
// must use invoke because the timer event is running on a separate thread
this.Invoke(new Action(() =>
{
MessageBox.Show("Message");
}));

Question to Auto logout C# desktop application

I need to implement an auto logout feature in C#. Previously i have asked a similiar question before and i managed to implement it using the System.Windows.Forms.Timer . But right now i have a additional requirement apart from resetting the timer when the user move the mouse or enters a key i also need to reset the timer when a new message is received via the serial port ( DataReceived event handler ).
serialPort.DataReceived += port_DataRecieved;
I need to include the reset function in a portion of the port_DataRecieved function. I cannot simply add another delegate method to the serialPort.DataReceived which will perform the reset as the serialPort.DataReceived will received a lot of other messages that i am not interested in. I want to perform a reset when the message that i am interested in arrives. And i know where to put the reset feature. The issue is that the timer does not reset in port_DataRecieved method. And i cannot achieve the desired result using the System.Threading.Timer. Anyone can guide me or provide some suggestion on this issue ? Any help provided will be greatly apperciated.
public partial class Form1: Form
{
private System.Windows.Forms.Timer sessionTimer = new System.Windows.Forms.Timer();
public Form1()
{
initialiseTimer();
}
private void port_DataRecieved(object sender, SerialDataReceivedEventArgs e)
{
try
{
serialPort= (SerialPort)sender;
str = serialPort.ReadExisting();
string[] split = str.Split(Convert.ToChar(10));
for (int i = 1; i < split.Length; i++)
{
str = split[i];
if (split[i].StartsWith("+CMTI:"))
{
sessionTimer.Stop();
sessionTimer.Start();
//Other codes
}
}
}
catch (Exception)
{
MessageBox.Show("Error processing received commands !", "CONNECTION ERROR", MessageBoxButtons.OK, MessageBoxIcon.Error);
sendRecPort.Close();
}
}
private void Form1_KeyDown(object sender, KeyEventArgs e)
{
sessionTimer.Stop();
sessionTimer.Start();
}
private void Form1_MouseMove(object sender, MouseEventArgs e)
{
sessionTimer.Stop();
sessionTimer.Start();
}
private void initialiseTimer()
{
sessionTimer.Interval = (5 * 60 * 1000);
sessionTimer.Tick += new EventHandler(logOutUser);
sessionTimer.Stop();
sessionTimer.Start();
}
private void logOutUser(object sender, EventArgs e)
{
// logout the user
this.Hide();
//Open up the login Form
login.Show();
}
}

Your problem is that the the DataReceived event is being executed on a thread other than the UI thread. You're trying to modify the timer (a UI object) from a non-UI thread. This typically throws an exception, but it's possible that the method that issues the DataReceived event is swallowing that exception.
From the documentation for the DataReceived event:
The DataReceived event is raised on a
secondary thread when data is received
from the SerialPort object. Because
this event is raised on a secondary
thread, and not the main thread,
attempting to modify some elements in
the main thread, such as UI elements,
could raise a threading exception. If
it is necessary to modify elements in
the main Form or Control, post change
requests back using Invoke, which will
do the work on the proper thread.
You need to synchronize with the UI thread to set the timer.
void ResetTimer()
{
sessionTimer.Stop();
sessionTimer.Start();
}
private void port_DataRecieved(object sender, SerialDataReceivedEventArgs e)
{
//Other codes
this.Invoke((MethodInvoker)delegate { ResetTimer(); });
//Other codes
}

I need to include the reset function in a portion of the port_DataReceived function.
Ok. Gotcha.
I cannot simply add another delegate method to the serialPort.DataReceived which will perform the reset as the serialPort.DataReceived will receive a lot of other messages that I am not interested in.
Ok, but I thought you said:
I want to perform a reset when the message that I am interested in arrives.
So you either have to listen to that DataReceived method, or you won't know when that message arrives.
I'm confused. What is it you want to do? Magic?
if (dataReceived == "someValue1")
{
//action if matches "someValue1"
}
else if (dataReceived.Contains("someValue2"))
{
// action if contains "someValue2"
}
else if (dataReceived.IndexOf("someValue3") != -1 )
{
// action if contains "someValue3"
}
else if (dataReceived == "someValue4")
{
// action if matches "someValue4"
}
else
{
// default action
}