C# COM Writing Error

The Terk · April 23rd, 2008, 10:42 PM

Hello everyone, I have what seems to be an easy problem, but I have yet to figure it out. I have downloaded the SimpleSerial program from this website and have modified it to execute a page request. When I run the form, I can select a serial port and can insert a command to request a specific page. The error is that when it begins writing data to the serial port, it continues to write the same data to the COM port. I only have one serialport.write function so I want to say that it keeps looping. Here is the code:

Code:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Net;
using System.IO;

namespace SimpleSerial
{
    public partial class Form1 : Form
    {
        // Add this variable 
        string RxString;
        string TxString;

        public Form1()
        {
            InitializeComponent();
        }

        private void buttonStart_Click(object sender, EventArgs e)
        {
            serialPort1.PortName = listBox1.Text;
            serialPort1.BaudRate = 38400;

            serialPort1.Open();
            if (serialPort1.IsOpen)
            {
                buttonStart.Enabled = false;
                buttonStop.Enabled = true;
                textBox1.ReadOnly = false;
            }
        }

        private void buttonStop_Click(object sender, EventArgs e)
        {
            if (serialPort1.IsOpen)
            {
                serialPort1.Close();
                buttonStart.Enabled = true;
                buttonStop.Enabled = false;
                textBox1.ReadOnly = true;
            }

        }

        private void Form1_FormClosing(object sender, FormClosingEventArgs e)
        {
            if (serialPort1.IsOpen) serialPort1.Close();
        }

        private void textBox1_KeyPress(object sender, KeyPressEventArgs e)
        {
            // If the port is closed, don't try to send a character.
            if (!serialPort1.IsOpen) return;

            // If the port is Open, declare a char[] array with one element.
            char[] buff = new char[1];

            // Load element 0 with the key character.
            buff[0] = e.KeyChar;

            // Send the one character buffer.
            //serialPort1.Write(buff, 0, 1);

            // Set the KeyPress event as handled so the character won't
            // display locally. If you want it to display, omit the next line.
            e.Handled = true;
        }

        private void DisplayText(object sender, EventArgs e)
        {
            textBox1.AppendText(RxString);
        }
        private void DisplayText2(object sender, EventArgs e)
        {
            textBox1.AppendText(TxString);
        }
        private void serialPort1_DataReceived(object sender, System.IO.Ports.SerialDataReceivedEventArgs e)
        {
            RxString = serialPort1.ReadTo("!");
            char option = RxString[0];
            switch (option)
            {
                case 'L':
                    {
                        getList();
                        serialPort1.Write(TxString);
                        break;
                    }
                case 'S':
                    {
                        getSale();
                        serialPort1.Write(TxString);
                        break;
                    }
                case 'I':
                    {
                        getInfo();
                        serialPort1.Write(TxString);
                        break;
                    }
                default: break;
            }
        }
        private void getList()
        {
            // used to build entire input
            StringBuilder sb = new StringBuilder();

            // used on each read operation
            byte[] buf = new byte[8192];
            char[] userid = new char[4];
            for (int i = 1; i < 5; i++)
            {
                userid[i - 1] = RxString[i];
            }


            serialPort1.DiscardInBuffer();

            string Id = new string(userid);

            // prepare the web page we will be asking for
            HttpWebRequest request = (HttpWebRequest)
                WebRequest.Create("http://192.168.1.101/IGLU/getlist.php?userid="+Id);

            // execute the request
            HttpWebResponse response = (HttpWebResponse)
                request.GetResponse();

            // we will read data via the response stream
            Stream resStream = response.GetResponseStream();

            //string tempString = null;
            int count = 0;

            do
            {
                // fill the buffer with data
                count = resStream.Read(buf, 0, buf.Length);
                // make sure we read some data
                if (count != 0)
                {
                    // translate from bytes to ASCII text
                    TxString = Encoding.ASCII.GetString(buf, 0, count);
                    // continue building the string
                    //sb.Append(TxString);
                }
            }
            while (count > 0); // any more data to read?
            this.Invoke(new EventHandler(DisplayText2));          //display to form
        }

        private void getSale()
        {
            // used to build entire input
            StringBuilder sb = new StringBuilder();

            // used on each read operation
            byte[] buf = new byte[8192];
            char[] saleid = new char[10];
            for (int i = 1; i < 11; i++)
            {
                saleid[i - 1] = RxString[i];
            }
            string upc = new string(saleid);

            // prepare the web page we will be asking for
            HttpWebRequest request = (HttpWebRequest)
                WebRequest.Create("http://192.168.1.101/IGLU/sale.php?upc=" + upc);

            // execute the request
            HttpWebResponse response = (HttpWebResponse)
                request.GetResponse();

            // we will read data via the response stream
            Stream resStream = response.GetResponseStream();

            //string tempString = null;
            int count = 0;

            do
            {
                // fill the buffer with data
                count = resStream.Read(buf, 0, buf.Length);
                // make sure we read some data
                if (count != 0)
                {
                    // translate from bytes to ASCII text
                    TxString = Encoding.ASCII.GetString(buf, 0, count);
                    // continue building the string
                    //sb.Append(TxString);
                }
            }
            while (count > 0); // any more data to read?
            this.Invoke(new EventHandler(DisplayText2));      //display to form
        }

        private void getInfo()
        {
            // used to build entire input
            StringBuilder sb = new StringBuilder();

            // used on each read operation
            byte[] buf = new byte[8192];
            char[] infoid = new char[10];
            for (int i = 1; i < 11; i++)
            {
                infoid[i - 1] = RxString[i];
            }
            string Id = new string(infoid);

            // prepare the web page we will be asking for
            HttpWebRequest request = (HttpWebRequest)
                WebRequest.Create("http://192.168.1.101/IGLU/info.php?upc=" + Id);

            // execute the request
            HttpWebResponse response = (HttpWebResponse)
                request.GetResponse();

            // we will read data via the response stream
            Stream resStream = response.GetResponseStream();

            //string tempString = null;
            int count = 0;

            do
            {
                // fill the buffer with data
                count = resStream.Read(buf, 0, buf.Length);
                // make sure we read some data
                if (count != 0)
                {
                    // translate from bytes to ASCII text
                    TxString = Encoding.ASCII.GetString(buf, 0, count);
                    // continue building the string
                    //sb.Append(TxString);
                }
            }
            while (count > 0); // any more data to read?
            this.Invoke(new EventHandler(DisplayText2));      //display to form
        }

        private void textBox1_TextChanged(object sender, EventArgs e)
        {

        }

        private void Form1_Load(object sender, EventArgs e)
        {

        }
    }
}

I am not to familiar with C# so any help would be awesome. Thanks guys

sr71000 · April 24th, 2008, 02:02 PM

from now on...if you're posting code, put it in the [ code] and the [ /code] tags. just take the space out in front word code in each bracket...makes it MUCH easier to read!!

Code:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Net;
using System.IO;

namespace SimpleSerial
{
	public partial class Form1 : Form
	{
		// Add this variable
		string RxString;
		string TxString;

		public Form1()
		{
			InitializeComponent();
		}

		private void buttonStart_Click(object sender, EventArgs e)
		{
			serialPort1.PortName = listBox1.Text;
			serialPort1.BaudRate = 38400;

			serialPort1.Open();
			if (serialPort1.IsOpen)
			{
				buttonStart.Enabled = false;
				buttonStop.Enabled = true;
				textBox1.ReadOnly = false;
			}
		}

		private void buttonStop_Click(object sender, EventArgs e)
		{
			if (serialPort1.IsOpen)
			{
				serialPort1.Close();
				buttonStart.Enabled = true;
				buttonStop.Enabled = false;
				textBox1.ReadOnly = true;
			}
		}

		private void Form1_FormClosing(object sender, FormClosingEventArgs e)
		{
			if (serialPort1.IsOpen)
				serialPort1.Close();
		}

		private void textBox1_KeyPress(object sender, KeyPressEventArgs e)
		{
			// If the port is closed, don't try to send a character.
			if (!serialPort1.IsOpen)
				return;

			// If the port is Open, declare a char[] array with one element.
			char[] buff = new char[1];

			// Load element 0 with the key character.
			buff[0] = e.KeyChar;

			// Send the one character buffer.
			//serialPort1.Write(buff, 0, 1);

			// Set the KeyPress event as handled so the character won't
			// display locally. If you want it to display, omit the next line.
			e.Handled = true;
		}

		private void DisplayText(object sender, EventArgs e)
		{
			textBox1.AppendText(RxString);
		}

		private void DisplayText2(object sender, EventArgs e)
		{
			textBox1.AppendText(TxString);
		}

		private void serialPort1_DataReceived(object sender, System.IO.Ports.SerialDataReceivedEventArgs e)
		{
			RxString = serialPort1.ReadTo("!");
			char option = RxString[0];
			switch (option)
			{
				case 'L':
				{
					getList();
					serialPort1.Write(TxString);
					break;
				}
				case 'S':
				{
					getSale();
					serialPort1.Write(TxString);
					break;
				}
				case 'I':
				{
					getInfo();
					serialPort1.Write(TxString);
					break;
				}
				default: break;
			}
		}

		private void getList()
		{
			// used to build entire input
			StringBuilder sb = new StringBuilder();

			// used on each read operation
			byte[] buf = new byte[8192];
			char[] userid = new char[4];
			for (int i = 1; i < 5; i++)
			{
				userid[i - 1] = RxString[i];
			}

			serialPort1.DiscardInBuffer();
			string Id = new string(userid);

			// prepare the web page we will be asking for
			HttpWebRequest request = (HttpWebRequest)
			WebRequest.Create("http://192.168.1.101/IGLU/getlist.php?userid="+Id);

			// execute the request
			HttpWebResponse response = (HttpWebResponse)
			request.GetResponse();

			// we will read data via the response stream
			Stream resStream = response.GetResponseStream();

			//string tempString = null;
			int count = 0;

			do
			{
				// fill the buffer with data
				count = resStream.Read(buf, 0, buf.Length);
				// make sure we read some data
				if (count != 0)
				{
					// translate from bytes to ASCII text
					TxString = Encoding.ASCII.GetString(buf, 0, count);
					// continue building the string
					//sb.Append(TxString);
				}
			}
			while (count > 0); // any more data to read?

			this.Invoke(new EventHandler(DisplayText2)); //display to form
		}

		private void getSale()
		{
			// used to build entire input
			StringBuilder sb = new StringBuilder();

			// used on each read operation
			byte[] buf = new byte[8192];
			char[] saleid = new char[10];
			for (int i = 1; i < 11; i++)
			{
				saleid[i - 1] = RxString[i];
			}
			string upc = new string(saleid);

			// prepare the web page we will be asking for
			HttpWebRequest request = (HttpWebRequest)
			WebRequest.Create("http://192.168.1.101/IGLU/sale.php?upc=" + upc);

			// execute the request
			HttpWebResponse response = (HttpWebResponse)
			request.GetResponse();

			// we will read data via the response stream
			Stream resStream = response.GetResponseStream();

			//string tempString = null;
			int count = 0;

			do
			{
				// fill the buffer with data
				count = resStream.Read(buf, 0, buf.Length);
				// make sure we read some data
				if (count != 0)
				{
					// translate from bytes to ASCII text
					TxString = Encoding.ASCII.GetString(buf, 0, count);
					// continue building the string
					//sb.Append(TxString);
				}
			}
			while (count > 0); // any more data to read?

			this.Invoke(new EventHandler(DisplayText2)); //display to form
		}

		private void getInfo()
		{
			// used to build entire input
			StringBuilder sb = new StringBuilder();

			// used on each read operation
			byte[] buf = new byte[8192];
			char[] infoid = new char[10];
			for (int i = 1; i < 11; i++)
			{
				infoid[i - 1] = RxString[i];
			}
			string Id = new string(infoid);

			// prepare the web page we will be asking for
			HttpWebRequest request = (HttpWebRequest)
			WebRequest.Create("http://192.168.1.101/IGLU/info.php?upc=" + Id);

			// execute the request
			HttpWebResponse response = (HttpWebResponse)
			request.GetResponse();

			// we will read data via the response stream
			Stream resStream = response.GetResponseStream();

			//string tempString = null;
			int count = 0;

			do
			{
				// fill the buffer with data
				count = resStream.Read(buf, 0, buf.Length);
				// make sure we read some data
				if (count != 0)
				{
					// translate from bytes to ASCII text
					TxString = Encoding.ASCII.GetString(buf, 0, count);
					// continue building the string
					//sb.Append(TxString);
				}
			}
			while (count > 0); // any more data to read?

			this.Invoke(new EventHandler(DisplayText2)); //display to form
		}

		private void textBox1_TextChanged(object sender, EventArgs e)
		{

		}

		private void Form1_Load(object sender, EventArgs e)
		{

		}
	}
}

The Terk · April 24th, 2008, 09:29 PM

I fixed the problem, turns out the receive buffer was never getting cleared, so i created an oldrxstring and if the two were the same i discarded the command. Thanks for the views guys

sr71000 · April 29th, 2008, 01:45 PM

Hey. Can you post the fixed code? I was trying to figure it out but I'd never worked with com ports before. I'd love to see how you fixed it!