CsvHelper : Writing List<string> to CSV

Question

I want to know how to write a List to a CSV using CsvHelper. I have taken a look here.

I have the following properties in the CSV Class

public class CSV
{
    public int? Id { get; set; }
    public List<string> Header1 { get; set; }
    public string Header2 { get; set; }
    public string Header3 { get; set; }
    public string Header4 { get; set; }
    public long? Header5 { get; set; }
    public long? Header6 { get; set; }
    public long? Header7 { get; set; }
    public string Header8 { get; set; }
    public List<string> Header9 { get; set; }
    public List<string> Header10 { get; set; }
    public List<string> Header11 { get; set; }
}

Writing to the CSV

var records = new List<CSV>
{
    new CSV { Header1 = new List<string>{ "value1", "value2" } }
};

using (var writer = new StreamWriter("path\\to\\file.csv"))
using (var csv = new CsvWriter(writer, CultureInfo.InvariantCulture))
{
    csv.WriteRecords(records);
}

The end result should look like this

Header1
value1,value2

Any help would be appreciated.

Answer 1

I'm guessing you are looking for something like this. This will create a comma separated string from the Header1 list.

public class Program
{
    static void Main(string[] args)
    {        
        var records = new List<CSV>
        {
            new CSV { Id = 1, Header1 = new List<string>{ "value1", "value2" } }
        };

        using (var csv = new CsvWriter(Console.Out, CultureInfo.InvariantCulture))
        {
            csv.Context.RegisterClassMap<CSVMap>();
            csv.WriteRecords(records);
        }

        Console.ReadKey();
    }
}

public class CSVMap : ClassMap<CSV>
{
    public CSVMap()
    {
        AutoMap(CultureInfo.InvariantCulture);
        Map(m => m.Header1).Convert(args => string.Join(",", args.Value.Header1)).Index(0);
    }
}

public class CSV
{
    public int? Id { get; set; }
    public List<string> Header1 { get; set; }
}

Giving you an output of

Id,Header1
1,"value1,value2"