C# Serial port- Not all data added to Listview

Question

so I am transmitting data from an Arduino to a C# Winform that outputs the data to a text box and saves it to a file. The format of the transmitted data is as follows 18|25|999|100~; the first part is the time in seconds which allows me to know when a line has been skipped(the Arduino runs a counter every second), the '~' character denotes line end. This data gets split up into an array(split by '|'), this array is then added to a Listview.

The data in the text box is perfect, all data is written, no line is skipped, but then I add the data to a listview and some lines are skipped.

  private void tData_TextChanged(object sender, EventArgs e)
    {
        if (logdata.Checked)
        {
            string output = tData.Text;
            string[] lines = output.Split('\n', '\r');
            string last_line = lines[lines.Length - 1];

            if (last_line.Contains("~"))
            {

                string output1 = tData.Text;
                string[] lines1 = output1.Split('\n', '\r');
                string last_line1 = lines1[lines.Length - 1];

                string[] splitdata = last_line1.Split('|');



                    //side task - not important
                    int time = Convert.ToInt32(Convert.ToString(splitdata[0]));

                    TimeSpan currenttime = TimeSpan.FromSeconds(time);


                    string str = currenttime.ToString(@"hh\:mm\:ss\:fff");
                    label2.Text = str;



                    //save to file
                    string path = "database.can";
                    using (StreamWriter sw = File.AppendText(path))
                    {
                        sw.WriteLine(last_line1);

                    }
                    //check if line exists to prevent doubles 
                    ListViewItem item = listView1.FindItemWithText(splitdata[0]);

                    if (item != null)
                    {
                    // it exists

                    }
                    else
                    {
                    //doesn't exist so add it
                    var listViewItem = new ListViewItem(splitdata);
                    listView1.Items.Add(listViewItem);

                    }



                }





            }
        }

tData is the text box where all the data is written. I would greatly appreciate if someone could help me prevent lines from being skipped, I've been pulling out my hair over this for the past few days. Thank you, Gabe

You blindly assume that the TextChanged event fired because only a single line got added. It fails miserably when the SerialPort received more than one line. That's bound to happen sooner or later, this code is quite expensive. Consider using SerialPort.ReadLine() so you can be sure you get one line at a time. Make that easy by using \n instead of ~ as the line terminator. And avoid trying to read it back from the TextBox, that's too expensive. — Hans Passant, Dec 12 '15 at 20:29
@HansPassant thanks for your comment, but since the arduino has a delay of 1 second on it and sends one line then how would two lines ever appear? The textchanged event is fired multiple times per line because each line is loaded by byte. I use the '~' character to denote line end — Gabe, Dec 12 '15 at 20:36
You wrote code that *can* fail this way. And it appears to fail this way. There is very little point in assuming that it won't fail this way, especially since you are seeing it fail this way. Just fix it so it can *never* happen. Write solid code instead of might-work code. — Hans Passant, Dec 12 '15 at 20:39
@HansPassant you are right, I haven't had enough experience in programming to get down to good habits. — Gabe, Dec 12 '15 at 20:59

Gabe · Accepted Answer · 2016-01-01T18:24:04.630

0

so I finally figured out(thanks to @hanspassant) that using Readline() fixes the problem, before all the bytes were read one at a time which caused some lines to be skipped

edited Jan 01 '16 at 18:24

answered Dec 29 '15 at 18:08

Gabe

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C# Serial port- Not all data added to Listview

1 Answers1