CSV Helper

CsvHelper is a library for reading and writing CSV files. Extremely fast, flexible, and easy to use. Supports reading and writing of custom class objects.

Install Packages

To install CsvHelper, run the following command:

Package Manager Console

PM> Install-Package CsvHelper

.NET CLI Console

> dotnet add package CsvHelper

Sample Utilities

A simple wrapper for basic usage.

using CsvHelper;
using System.Collections.Generic;
using System.IO;
using System.Linq;

namespace CsvTest
{
    public class CsvUtils
    {
        public static List<T> GetRecords<T>(string path)
        {
            using (var sr = new StreamReader(path))
            {
                var reader = new CsvReader(sr);
                return reader.GetRecords<T>().ToList();
            }
        }

        public static void WriteRecords<T>(List<T> records, string path)
        {
            using (var sw = new StreamWriter(path, false, System.Text.Encoding.UTF8))
            {
                var writer = new CsvWriter(sw);
                writer.WriteRecords(records);
            }
        }

        public static void WriteDictionaryRecords(List<Dictionary<string, object>> records, string path, bool includeHeader = true)
        {
            using (var sw = new StreamWriter(path))
            {
                var writer = new CsvWriter(sw);

                bool headerInited = includeHeader ? false : true;

                foreach (var record in records)
                {
                    if (!headerInited)
                    {
                        headerInited = true;
                        foreach (var kvp in record)
                        {
                            writer.WriteField(kvp.Key);
                        }
                        //ensure write end of record after the header
                        writer.NextRecord();
                    }

                    //write record field by field
                    foreach (var kvp in record)
                    {
                        writer.WriteField(kvp.Value);
                    }

                    //ensure write end of record when using WriteField method
                    writer.NextRecord();
                }
            }
        }
    }
}

Sample Extensions

A sample extensions to write dynamic objects by using ExpandoObject

using System.Collections.Generic;
using System.Dynamic;

namespace CsvTest
{
    public static class DictionaryCsvExtentions
    {
        public static dynamic BuildCsvObject(this Dictionary<string, object> document)
        {
            dynamic csvObj = new ExpandoObject();

            foreach (var p in document)
            {
                AddProperty(csvObj, p.Key, p.Value);
            }

            return csvObj;
        }

        private static void AddProperty(ExpandoObject expando, string propertyName, object propertyValue)
        {
            var expandoDict = expando as IDictionary<string, object>;
            if (expandoDict.ContainsKey(propertyName))
            {
                expandoDict[propertyName] = propertyValue;
            }
            else
            {
                expandoDict.Add(propertyName, propertyValue);
            }
        }
    }
}

Sample Usage

class Program
{
    public class Person
    {
        public string Name { get; set; }
        public string Gender { get; set; }
        public DateTime BirthDate { get; set; }
    }

    static void Main(string[] args)
    {
        string path = "persons.csv";

        if (System.IO.File.Exists(path))
            System.IO.File.Delete(path);

        // Write into CSV
        var data = new List<Person>
        {
            new Person { Name = "Steven", Gender = "M", BirthDate = new DateTime(1985, 1, 1) },
            new Person { Name = "Cherry", Gender = "F", BirthDate = new DateTime(2003, 2, 3) },
            new Person { Name = "Angie", Gender = "F", BirthDate = new DateTime(2008, 11, 15) }
        };
        CsvUtils.WriteRecords(data, path);

        // Read from CSV
        var persons = CsvUtils.GetRecords<Person>(path);
        foreach (var person in persons)
        {
            Console.WriteLine($"{person.Name} ({person.Gender}) - {person.BirthDate.ToShortDateString()}");
        }
    }
}

Resource

• Official Documentation