Parsing CSV Files in C#, With Header

Parsing CSV files in C#, with header

Let a library handle all the nitty-gritty details for you! :-)

Check out FileHelpers and stay DRY - Don't Repeat Yourself - no need to re-invent the wheel a gazillionth time....

You basically just need to define that shape of your data - the fields in your individual line in the CSV - by means of a public class (and so well-thought out attributes like default values, replacements for NULL values and so forth), point the FileHelpers engine at a file, and bingo - you get back all the entries from that file. One simple operation - great performance!

C# Reading CSV File | with header Row and Comma Separated Values

Since you mention the option of using CsvHelper - it should be fairly straightforward for you use it to map straight to your POCO. Assuming a simple object:

public class Foo 
{
    public string Bar1 {get;set;}
    public string Bar2 {get;set;}
    public string Bar3 {get;set;}
    public string Bar4 {get;set;}
    public string Bar5 {get;set;}
}

Define a class map

internal sealed class MyCsvMap : ClassMap<Foo>
{
    public MyCsvMap()
    {
        Map(x => x.Bar1).Name("Header 1");
        Map(x => x.Bar2).Name("Header 2");
        Map(x => x.Bar3).Name("Header 3");
        Map(x => x.Bar4).Name("Header 4");
        Map(x => x.Bar5).Name("Header5");
    }
}

And then simply

using (var sr = new StreamReader(csvFile.FullName))
{
    using (var csvReader = new CsvReader(sr))
    {
        csvReader.Configuration.RegisterClassMap<MyCsvMap>();
        return csvReader.GetRecords<Foo>().ToList();
    }
}

CsvHelper should automatically deal with your quoted fields - delimiters within double quotes are ignored by the default setting of Configuration.Quote.

How to extract header from csv in c#

If I understood correctly, you need to read the whole file, process all the lines except the header, then write back a different file with the header and the processed lines, right?

If so, the following approach should work:

var allLines = File.ReadAllLines(originalFile);
var headerLine = allLines.First();
var dataLines = allLines.Skip(1);
var processedLines = ProcessLines(dataLines);
File.WriteAllLines(newFile, (new[] {headerLine}.Concat(processedLines)).ToArray());

The ProcessLines method would accept the original lines as parameter and return a list with the processed lines:

IEnumerable<string> ProcessLines(IEnumerable<string> originalLines)
{
    var processedLines = new List<string>();
    foreach(var line in originalLines)
    {
        var processedLine = //generate your processed line here
        processedLines.Add(processedLine);
    }
    return processedLines;
}

Reading dynamic header from csv file

You could try as below to make the pointer on the right place

 using (var reader = new StreamReader(file.OpenReadStream()))
                {
                    reader.ReadLine();
                    // it was not used to read text but adjust  the position of pointer, in your case,you need add the codes for 10 times 
                    reader.ReadLine();
                    reader.ReadLine();
                    using (var csvReader = new CsvReader(reader, CultureInfo.CurrentCulture))
                    {
                        var records = csvReader.GetRecords<TestModel>().ToList();
                    }
    
                    
                } 

Result:

also,open your csv file as below and check if the name contains sapce,it may also cause the error you've shown
Correct:

Wrong:

Reading CSV files using C#

Don't reinvent the wheel. Take advantage of what's already in .NET BCL.

• add a reference to the Microsoft.VisualBasic (yes, it says VisualBasic but it works in C# just as well - remember that at the end it is all just IL)
• use the Microsoft.VisualBasic.FileIO.TextFieldParser class to parse CSV file

Here is the sample code:

using (TextFieldParser parser = new TextFieldParser(@"c:\temp\test.csv"))
{
    parser.TextFieldType = FieldType.Delimited;
    parser.SetDelimiters(",");
    while (!parser.EndOfData) 
    {
        //Processing row
        string[] fields = parser.ReadFields();
        foreach (string field in fields) 
        {
            //TODO: Process field
        }
    }
}

It works great for me in my C# projects.

Here are some more links/informations:

• MSDN: Read From Comma-Delimited Text Files in Visual Basic
• MSDN: TextFieldParser Class

Parse CSV data based on Headers then load into Array

You can split every line with String.Split method.
Like

var fields = sLine.Split(new char[]{','});

if your values are separated by comma

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