How to read lines from a CSV file

ddanbe 0 3K Views

The test.txt file I'm using is:

1,2,3,Name1,Pizza,Pizza Hut,7,8,9
1,2,3,Name2,goose,my home,7,8,9
1,2,3,Name3,chicken,airplane,7,8,9

Most of the explanation can be found in the snippet.
Some CSV(Comma Separated Value) files often contain as first line, a header.
You could skip this, or threat it a bit differently.
I had no header, so I leave the coding of that up to you.
I made the test.txt file with Notepad, started a new windowsapplication and filled in this extra code in the Form1 constructor.
Enjoy!

public Form1()
        {
            InitializeComponent();

            const char fieldSeparator = ',';
            string filePath = @"C:\test.txt";
            using (StreamReader SR = new StreamReader(filePath))    // the way to go
            {
                // while not end of file do
                // could also be (SR.Peek() != -1) or something like
                // ((currentLine = sr.ReadLine()) != null) :{
                while (!SR.EndOfStream) //best way to do it
                {
                    //read a line of our file and split it into its separate values
                    var CSValues = SR.ReadLine().Split(fieldSeparator);

                    // instead of var, you could use string[] or List<string> 
                    // in the case of List<string> use the following
                    // List<string> CSValues = SR.ReadLine().Split(fieldSeparator).ToList();

                    // Now you can do anything you want with this collection of CSValues
                    // Index the list to get just the values we want and as an example, 
                    // suppose we are only interested in the 4th, 5th and 6th columnvalues:
                    // just show them in a MessageBox, separated by spaces and vertical bars
                    MessageBox.Show( CSValues[3] + " | " + CSValues[4] + " | " + CSValues[5]);
                }
            }
Member Avatar for Kratoswoo
Kratoswoo 0 Newbie Poster

Here is how I did it with a .csv file and it puts the information into the textbox

private void btnSearch_Click(object sender, EventArgs e)
        {
            string filepath = "C:***.csv";
            using (StreamReader readFile = new StreamReader(filepath))
            {
                string line;
                while ((line = readFile.ReadLine()) != null)
                {
                    IList<string> split = Regex.Split(line, ",(?=(?:[^\"]*\"[^\"]*\")*[^\"]*$)");
                    int count = 0;

                    foreach (string ln in split)
                    {
                        if (count > 4 && count < 6)
                        {
                            textBox1.Text += ("Name" + " '"+ split[6] + "','" + split[7] + "','" + "," + "," + "'" + split[5] + "'" + Environment.NewLine);
                        }

                        count++;
                    }
                }
            }
        }
Edited by Kratoswoo
Member Avatar for Lucaci Andrew
Lucaci Andrew 140 Za s|n

Here's a small Linq example:

public static IEnumerable<string[]> Read(string path)
{
    return from line in File.ReadLines(path)
                    select line.Split(new [] {','});
}
ddanbe commented: He! Nice addition. +15
Member Avatar for deceptikon
deceptikon 1,790 Code Sniper
  1. Read the documentation
  2. ???
  3. Profit

I've written too many CSV parsers (real ones, not this naive comma split stuff) to be interested in doing it again. ;)

Edited by deceptikon
ddanbe commented: Great! +15
Member Avatar for ddanbe
ddanbe 2,724 Professional Procrastinator

He, deceptikon, thanks for sharing. Did not know this class even existed! Tell me about CVS parsing, let's say it was the main part of my professional programmining tasks, way back in the previous century.

Member Avatar for deceptikon
deceptikon 1,790 Code Sniper

The VisualBasic namespace has a lot of cool stuff that really shouldn't be there because it's too well hidden. FileLogTraceListener comes immediately to mind as I've been using it a lot lately.

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