Serial Port Received data continues without button click

Question

3.00/5 (2 votes)

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I've made a GUI in WPF to read data via RS232 and.
The only problem is I have to keep pressing
a button to send a 'Receive data' command to my controller
via RS232 so it sends the data back. I want to implement
this in continuously/real time so I don't have to keep
pressing a button to communicate with my device. I've
written while loops and that just freezes my program, i've
also tried a checkbox so if it's checked it gets data and
that also freezes the GUI.

Just wanted to know if there is any solution in C# and wpf

C#

SerialPort sp;
  sp.DataReceived += new SerialDataReceivedEventHandler(receive);


 private void receive(object sender, SerialDataReceivedEventArgs e)
        {
                string data;
                data = sp.ReadExisting();
                MyLog(data);
        }
private void MyLog(string msg)
        {

                this.Dispatcher.Invoke(new DisplayTextDelegate(DisplayText), msg);
        }
        private void DisplayText(string text)
        {
             TextBox2.AppendText(text);
        }

        private void SendButton_Click(object sender, RoutedEventArgs e)
        {

             sp.Write(TextBox1.Text+ "\r\n");

        }

Posted 16-Mar-12 5:55am

getanswer

Updated 16-Mar-12 10:56am

Clifford Nelson

v2

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Clifford Nelson · Answer 1 · 2012-03-16T08:56:00

Solution 2

This may be a little more help:

C#

public MainWindow()
{
  InitializeComponent();

  var bw = new BackgroundWorker();
  bw.DoWork += new DoWorkEventHandler(bw_DoWork);
  bw.WorkerSupportsCancellation = true;
  bw.WorkerReportsProgress = true;
  bw.ProgressChanged += new ProgressChangedEventHandler(bw_ProgressChanged);
  bw.RunWorkerAsync();

}

void bw_ProgressChanged(object sender, ProgressChangedEventArgs e)
{
  //Update UI here
  var newText = e.UserState;
}

void bw_DoWork(object sender, DoWorkEventArgs e)
{
  var bw = (BackgroundWorker) sender;
  while (!bw.CancellationPending)
  {
    //Do RS-232 stuff here
    var newText = "Put new information here";
    bw.ReportProgress(1, newText);
  }
}

Posted 16-Mar-12 8:56am

Clifford Nelson

Comments

getanswer 16-Mar-12 15:49pm

Hello Clifford Nelson , thx for quick response

here is my code
SerialPort sp;
sp.DataReceived += new SerialDataReceivedEventHandler(receive);

private void receive(object sender, SerialDataReceivedEventArgs e)
{
string data;
data = sp.ReadExisting();
MyLog(data);
}
private void MyLog(string msg)
{

this.Dispatcher.Invoke(new DisplayTextDelegate(DisplayText), msg);
}
private void DisplayText(string text)
{
TextBox2.AppendText(text);
}

private void SendButton_Click(object sender, RoutedEventArgs e)
{

sp.Write(TextBox1.Text+ "\r\n");

}

can you tell me where should i apply these code in BackGroundWorker,thanks
TextBox1 is for sending Data, TextBox2 is receiving data,

Clifford Nelson 16-Mar-12 16:53pm

Hey. I was looking at the problem now that I have seen the code. I suspect you got hung up because the port was not open. I would recommend that you look at http://www.dreamincode.net/forums/topic/35775-serial-port-communication-in-c%23/ Download the code and see if you can figure what your problem is. I really do not have a setup here to test a serial port.

[no name] 16-Mar-12 18:38pm

It's not that the port is not open, the problem is that he apparently wants someone to write the code for him. You got my 5 for at least writing that much for him.

getanswer 16-Mar-12 17:08pm

Hi , i have seen these code already, i tried with these code but i failed, with BackgroundWorker, i dont know which place i have to set my code, i tried but getting some problem, anybody with code please not URL link. thanks

[no name] 16-Mar-12 18:36pm

"i failed" and "some problem" mean absolutely nothing to anyone trying to help you. What do you mean you don't know which place to put your code? Did you miss the "Do RS232 stuff here" or did you not read the answer?

getanswer 17-Mar-12 7:42am

hello wes aday ,exactly RS232 stuff, i have receive and send eventhandlers, and in Window_Loaded i did other things like sp.open() and giving ,baudrate,parity...my question is in BackGroundWorker i tried putting Send stuff and receive stuff, but output is not in continues. i appreciate clifford Nelson did good job

[no name] 17-Mar-12 9:56am

THAT right there is exactly your problem. "but output is not in continues" what the heck does that even mean? Did it work once? Did it work twice and stop? Did the thread not start at all? What did you see when you stepped through the code with your debugger? YOU need to tell us these things! You have to help us before we can even begin to help you. We cannot see your code. We cannot see your errors. We cannot see your debugger. You have to actually break down and do something for yourself. Sorry if that sounds harsh but you have been given the answers and all you can do is whine about it not working.

getanswer 17-Mar-12 13:07pm

public partial class Window1 : Window,INotifyPropertyChanged
{

delegate void DisplayTextDelegate(string text);
SerialPort sp = new SerialPort();
public string[] portnames = SerialPort.GetPortNames();
public Window1()
{
InitializeComponent();
var bw = new BackgroundWorker();
bw.DoWork += new DoWorkEventHandler(bw_DoWork);
bw.WorkerSupportsCancellation = true;
bw.WorkerReportsProgress = true;
bw.ProgressChanged += new ProgressChangedEventHandler(bw_ProgressChanged);
bw.RunWorkerAsync();

textBox1.DataContext = this;

}
void bw_ProgressChanged(object sender, ProgressChangedEventArgs e)
{
str = textBox2.Text.ToString();

sp.Write("[" + com.Text + "]:" + str + "\r\n");
var newText = e.UserState;
}

void bw_DoWork(object sender, DoWorkEventArgs e)
{
var bw = (BackgroundWorker)sender;
while (!bw.CancellationPending)
{
string data;
data = sp.ReadExisting();
MyLog(data);

var newText = "str";
bw.ReportProgress(1, newText);
}
}

private void Window_Loaded(object sender, RoutedEventArgs e)
{
sp.ReadTimeout = 500;
sp.WriteTimeout = 500;
sp.DtrEnable = true;
sp.Handshake = Handshake.None;

foreach (string s in portnames)
{
com.ItemsSource = OrderedPortNames();

}
}
private void button1_Click(object sender, RoutedEventArgs e)
{
bool error = false;
sp = new System.IO.Ports.SerialPort("COM1",9600Parity.None, 8, StopBits.One);

sp.DataReceived += new SerialDataReceivedEventHandler(receive);

if (sp.IsOpen)
sp.Close();
else
{
try
{
sp.Open();

}
catch (UnauthorizedAccessException) { error = true; }
catch (ArgumentException) { error = true; }
catch (IOException) { error = true; }
if (error)
{
MessageBox.Show(" couldn't open " + com.Text + " ,it is already opened ");
}

}
}
public event PropertyChangedEventHandler PropertyChanged;
public void NotifyPropertyChanged(string propertyName)
{
if (PropertyChanged != null)
{
PropertyChanged(this,
new PropertyChangedEventArgs(propertyName));
}
}
private string message;
public string Message
{
get { return message; }
set
{
message = value;
NotifyPropertyChanged("Message");
}
}
private void receive(object sender, SerialDataReceivedEventArgs e)
{ string data;
data = sp.ReadExisting();
MyLog(data);
}

private void MyLog(string msg)
{
this.Dispatcher.Invoke(new DisplayTextDelegate(DisplayText), msg);
}
private void DisplayText(string text)
{
Message += text;
}

string str;
private void Senddata_Click(object sender, RoutedEventArgs e)
{
str = textBox2.Text.ToString();

sp.Write( str + "\r\n");

}

private void Close_Click(object sender, RoutedEventArgs e)
{
if (sp.IsOpen)
{
sp.Close();

}
e

sjelen · Answer 2 · 2012-03-16T06:51:00

Solution 1

Use System.ComponentModel.BackgroundWorker and put your code in it's DoWork event.
That way RS232 reading will happen in background and will not block GUI.
Your button (or checkbox) should then start/stop this BackgroungWorker.
There are many examples how to use BackgroundWorker properly and how to update GUI based on it's processing.

Posted 16-Mar-12 6:51am

sjelen

Updated 16-Mar-12 6:53am

v2

Comments

getanswer 18-Mar-12 8:21am

Hi all, any updates for my question please, waiting for someone answer....

sjelen 19-Mar-12 10:08am

Why downvote this solution? It's the same as Clifford's.
Don't downvote something only because you're too lazy to do some research.

getanswer 19-Mar-12 10:32am

hi sjelen, downvote ,sorry i did not seen that, am not lazy ,i tried my best ..i dont know where am wrong if you know solution please let me know, thanks

sjelen 19-Mar-12 11:48am

The code under your question is correct. You need to provide more details about your application if you want more help, as Wes Aday said.
Does it work at all? Does it work only once?
Is the device connected to RS232 supposed to send data continuously, or you need to send 'read' command to it every time?
The code inyour question does not match the code in your comment above. Which one do you use?

getanswer 19-Mar-12 11:52am

hi,i did used BackGroundWorker till now it giving only once receivingdata , so i did If checkbox is checked , while loop , and DispatcherTimer, with this am sending data continuously, but GUI is Freezing,
if(CheckBox.IsChecked)
{
while (sp.BytesToRead > 0)
{
string data = sp.ReadExisting();
this.Dispatcher.Invoke(new System.Windows.Forms.MethodInvoker(delegate()
{
textBox1.Text+= data;

}));
}
}

so i want to use with BackGroundWorker Please

sjelen 19-Mar-12 12:23pm

Where exactly did you put this code? In a button click handler? Or in BackgroundWorker DoWork handler?

getanswer 19-Mar-12 12:48pm

in a BackgroundWorker DoWork

sjelen 19-Mar-12 13:37pm

Again, there is nothing wrong with this piece of code. The error must be somewhere else. If you can, post all your code, maybe we can find what's wrong.
What kind of device is attached to serial port?
Are you sure device is sending data continuously? You might need to write something to serial port every time before you can read from it.

getanswer 19-Mar-12 15:47pm

hi sjelen here is my code, i did with DispatcherTimer, everysecond it reads data from TextBox2.Text ,i.e., sending data to serialport, i gave checkbox.ischecked in while loop it reads, here is the problem ,th GUI freezing i cant do anything after that,so i want to do in BackGroundWorker as
Clifford Nelson said, i tried but data is not reading, and it says port is closed and , these data is using another thread, please let me know how to use these code in BackGroundWorker orelse in Threading if possible, thanks

namespace WpfApplication2
{

public partial class Window1 : Window,INotifyPropertyChanged
{

delegate void DisplayTextDelegate(string text);
SerialPort sp = new SerialPort();

public Window1()
{
InitializeComponent();
textBox1.DataContext = this;

}

private void Window_Loaded(object sender, RoutedEventArgs e)
{
string[] portnames = SerialPort.GetPortNames();
foreach (string s in portnames)
{
com.ItemsSource = OrderedPortNames();

}

sp.DtrEnable = true;
sp.Handshake = Handshake.None;

DispatcherTimer dispatcherTimer1 = new DispatcherTimer();
dispatcherTimer1.Tick += new EventHandler(dispatcherTimer1_Tick);
dispatcherTimer1.Interval = new TimeSpan(0, 0, 2);
dispatcherTimer1.Start();

}

private void button1_Click(object sender, RoutedEventArgs e)
{
bool error = false;
if (sp.IsOpen)
sp.Close();
else
{
try
{
sp = new System.IO.Ports.SerialPort(com.Text, Convert.ToInt32(baud.Text), Parity.None, Convert.ToInt32(bitrat.Text), StopBits.One);
sp.DataReceived += new SerialDataReceivedEventHandler(datareceive);
sp.Open();

}
catch (UnauthorizedAccessException) { error = true; }
catch (ArgumentException) { error = true; }
catch (IOException) { error = true; }
if (error)
{
MessageBox.Show(" couldn't open " + com.Text + " ,it is already opened ");
}

}

}
public event PropertyChangedEventHandler PropertyChanged;
public void NotifyPropertyChanged(string propertyName)
{
if (PropertyChanged != null)
{
PropertyChanged(this,
new PropertyChangedEventArgs(propertyName));
}
}
private string message;
public string Message
{
get { return message; }
set
{ message = value;
NotifyPropertyChanged("Message");
}
}

private void datareceive(object sender, SerialDataReceivedEventArgs e)
{

while (sp.BytesToRead > 0)
{
string data = sp.ReadExisting();
this.Dispatcher.Invoke(new System.Windows.Forms.MethodInvoker(delegate()
{
Message += data;
}));
}

}

private void MyLog(string msg)
{
this.Dispatcher.Invoke(new DisplayTextDelegate(DisplayText), msg);

}
private void DisplayText(string text)
{
Message += text;
}

string str;
private void senddata_Click(object sender, RoutedEventArgs e)
{
str = textBox2.Text.ToString();

sp.Write(str + "\r\n");

}

private void button2_Click(object sender, RoutedEventArgs e)
{
if (sp.IsOpen)

getanswer 20-Mar-12 15:11pm

Hi any solution from your side please........let me know