Cookbooks
C#
Chapter 10. Data Formats and Serialization
Working with CSV

C#:
Working with CSV

How to:

Working with CSV files in C# can be accomplished through the System.IO namespace for basic operations, and for more complex manipulations or to handle larger files seamlessly, one might consider third-party libraries like CsvHelper. Below are examples of how to read from and write to CSV files using both approaches.

Reading a CSV file using System.IO 

using System;
using System.IO;

class ReadCSV
{
    static void Main()
    {
        string filePath = @"path\to\your\file.csv";
        // Reading all the lines of the CSV file
        string[] csvLines = File.ReadAllLines(filePath);
        
        foreach (string line in csvLines)
        {
            string[] rowData = line.Split(',');
            Console.WriteLine($"First Column: {rowData[0]}, Second Column: {rowData[1]}");
        }
    }
}

Sample output:

First Column: Name, Second Column: Age
First Column: John Doe, Second Column: 30

Writing to a CSV file using System.IO 

using System;
using System.Collections.Generic;
using System.IO;

class WriteCSV
{
    static void Main()
    {
        string filePath = @"path\to\your\output.csv";
        var lines = new List<string>
        {
            "Name,Age",
            "John Doe,30",
            "Jane Smith,25"
        };
        
        File.WriteAllLines(filePath, lines);
        Console.WriteLine("CSV file written.");
    }
}

Sample output:

CSV file written.

Using CsvHelper to Read CSV

To use CsvHelper, first, add the CsvHelper package to your project using NuGet Package Manager.

using CsvHelper;
using System.Globalization;
using System.IO;
using System.Linq;
using CsvHelper.Configuration;

class ReadCSVWithCsvHelper
{
    static void Main()
    {
        string filePath = @"path\to\your\file.csv";

        using (var reader = new StreamReader(filePath))
        using (var csv = new CsvReader(reader, CultureInfo.InvariantCulture))
        {
            var records = csv.GetRecords<dynamic>().ToList();
            foreach (var record in records)
            {
                Console.WriteLine($"First Column: {record.Name}, Second Column: {record.Age}");
            }
        }
    }
}

Sample output:

First Column: John Doe, Second Column: 30
First Column: Jane Smith, Second Column: 25

Using CsvHelper to Write CSV 

using CsvHelper;
using System.Globalization;
using System.IO;
using System.Collections.Generic;
using CsvHelper.Configuration;

class WriteCSVWithCsvHelper
{
    public class Person
    {
        public string Name { get; set; }
        public int Age { get; set; }
    }

    static void Main()
    {
        string filePath = @"path\to\your\output.csv";
        var records = new List<Person>
        {
            new Person { Name = "John Doe", Age = 30 },
            new Person { Name = "Jane Smith", Age = 25 }
        };

        using (var writer = new StreamWriter(filePath))
        using (var csv = new CsvWriter(writer, CultureInfo.InvariantCulture))
        {
            csv.WriteRecords(records);
        }
        
        Console.WriteLine("CSV file written with CsvHelper.");
    }
}

Sample output:

CSV file written with CsvHelper.
Working with JSON