using System;

using ChoETL;

using System.Collections.Generic;

using System.Linq;

using System.Text;

​

public class Program

{

    public static void Main()

    {

        string csv1 = @"col1, col2, col3

val1, val2, val3

val11, val21, val31";

        string csv2 = @"col1, col3

val4, val5

val41, val51";

        string csv3 = @"col1, col4

val6, val7

val61, val71";

        ChoCSVRecordConfiguration config = null;

        List<object> items = new List<object>();

        using (var r1 = ChoCSVReader.LoadText(csv1).WithFirstLineHeader())

        {

            using (var r2 = ChoCSVReader.LoadText(csv2).WithFirstLineHeader())

            {

                using (var r3 = ChoCSVReader.LoadText(csv3).WithFirstLineHeader())

                {

                    items.Add(r1.First());

                    items.Add(r2.First());

                    items.Add(r3.First());

                }

            }

        }

​

        StringBuilder csv = new StringBuilder();

        using (var w = new ChoCSVWriter(csv)

               .WithFirstLineHeader()

               .WithMaxScanRows(5)

               .ThrowAndStopOnMissingField(false)

              )

        {

            w.Write(items);

​

            //Capture configuration for later use to merge CSV files

            config = w.Configuration;

        }

​

        using (var r1 = ChoCSVReader.LoadText(csv1).WithFirstLineHeader())

        {

            using (var r2 = ChoCSVReader.LoadText(csv2).WithFirstLineHeader())

            {

                using (var r3 = ChoCSVReader.LoadText(csv3).WithFirstLineHeader())

                {

                    //use the captured configuration object for merging CSV file

                    using (var w = new ChoCSVWriter(Console.Out, config)

                           .WithFirstLineHeader()

                          )

                    {

                        w.Write(Enumerable.Concat(r1, r2).Concat(r3));

                    }

                }

            }

        }

    }

}