CODEWITHSUNDEEP
c#wpfmultithreadingserial-port
user2261524
user2261524

Reputation: 415

Serial port reading + Threads or something better?

I dont know if this is a good way to work with a stack for this task but I'm sure there is a faster way ... I get data from my microcontroller but the data length is not always the same length. I thought maybe I can push data in my stack and in a thread I can pop it and decode the message. I didnt wanted slow down the DataReceivedHandler so then I created a Thread which can pop the data and write it to my Listview in my decodeMessage() function.

After a short time I get a System.OutOfMemories Exception..

Any ideas how I can do it in a better way ?

I'm reading from my serial port just when data arrives here: 

Stack<byte[]> stack = new Stack<byte[]>();

.....

public void DataReceivedHandler(object sender, SerialDataReceivedEventArgs e)
{
    SerialPort sp = (SerialPort)sender;
    byte[] data = new byte[sp.BytesToRead];
    sp.Read(data, 0, data.Length);

    stack.Push(data);
}

And this is my Thread:

private void formatData()
{
    try
    {
        while (true)
        {
            byte[] data;
            int i=0;

            Dispatcher.BeginInvoke(new Action(() =>
            {
                while (stack.Count > 0)
                {
                    data = stack.Pop();
                    while (i < data.Length)
                    {
                        decodeMessage(data[i]);
                        i++;
                    }
                }
            }));          
        }
    }
    catch (Exception ex)
    {
        System.Windows.Forms.MessageBox.Show(ex.ToString(), "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
    }
}

thx

Upvotes: 0

Views: 12720

Answers (1)

user2019047
user2019047

Reputation: 769

This code use a thread safe queue. I simplified some of my own code, so this code is not tested or compiled. If you have problems compiling or it produce errors, add a comment to me and I will help you out.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO.Ports;
using System.Windows.Threading;
using System.Collections.Concurrent;

void someRoutine()
{
    // initialize queue before using it
    serialDataQueue = new ConcurrentQueue<char>();

}


/// <summary>
/// data from serialPort is added to the queue as individual chars, 
/// a struct may be better
/// </summary>
public ConcurrentQueue<char> serialDataQueue;

// get data
void _serialPort_DataReceived(object sender, SerialDataReceivedEventArgs e)
{
    SerialPort sp = sender as SerialPort;
    int bytesAvailable = sp.BytesToRead;

    // array to store the available data    
    char[] recBuf = new char[bytesAvailable];

    try
    {    
        // get the data
        sp.Read(recBuf, 0, bytesAvailable);

        // put data, char by char into a threadsafe FIFO queue
        // a better aproach maybe is putting the data in a struct and enque the struct        
        for (int index = 0; index < bytesAvailable; index++)
           serialDataQueue.Enqueue(recBuf[index]);

    }
    catch (TimeoutException ex)
    {
        // handle exeption here
    }
}



/// <summary>
/// Check queue that contains serial data, call this 
/// routine at intervals using a timer or button click
/// or raise an event when data is received
/// </summary>
private void readSearialDataQueue()
{
    char ch;

    try
    {
        while (serialDataQueue.TryDequeue(out ch))
        {
            // do something with ch, add it to a textbox 
            // for example to see that it actually works
            textboxDataReceived.Text += ch;
        }

    }
    catch (Exception ex)
    {
        // handle ex here
    }
}

Upvotes: 4

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