How to keep quotes when parsing csv file?

Question

I am using Microsoft.VisualBasic.FileIO.TextFieldParser to read a csv file, edit it , then parse it.

The problem is the quotes are not being kept after parsing.

I tried using parser.HasFieldsEnclosedInQuotes = true; but it does not seem to keep the quotes for some reason.

This issue breaks when a field contains a quote for example : Before

 "some, field" 

After

 some, field 

As two seperate fields

Here is my method

public static void CleanStaffFile()
    {
        String path = @"C:\file.csv";
        String dpath = String.Format(@"C:\file_{0}.csv",DateTime.Now.ToString("MMddyyHHmmss"));
        List<String> lines = new List<String>();

        if (File.Exists(path))
        {
            using (TextFieldParser parser = new TextFieldParser(path))
            {
                parser.HasFieldsEnclosedInQuotes = true;
                parser.Delimiters = new string[] { "," };

                while (!parser.EndOfData)
                {
                    string[] parts = parser.ReadFields();

                    if (parts == null)
                    {
                        break;
                    }

                    if ((parts[12] != "") && (parts[12] != "*,116"))
                    {
                        parts[12] = parts[12].Substring(0, 3);
                    }
                    else
                    {
                        parts[12] = "0";
                    }

                    lines.Add(string.Join(",", parts));
                }
            }

            using (StreamWriter writer = new StreamWriter(dpath, false))
            {
                foreach (String line in lines)
                    writer.WriteLine(line);
            }

        }

        MessageBox.Show("CSV file successfully processed :\n");
    }

Answer 1

So you want to have quotes after you have modified it at string.Join(",", parts)? Then it's easy since only fields which contain the separator were wrapped in quotes before. Just add them again before the String.Join.

So before (and desired):

"some, field" 

after(not desired):

some, field 

This should work:

string[] fields = parser.ReadFields();
// insert your logic here ....
var newFields = fields 
    .Select(f => f.Contains(",") ? string.Format("\"{0}\"", f) : f);
lines.Add(string.Join(",", newFields));

Edit

I would like to keep quotes even if doesn't contain a comma

Then it's even easier:

var newFields = fields.Select(f => string.Format("\"{0}\"", f));