CsvHelper - read in multiple columns to a single list

Neil picture Neil · Jun 27, 2013 · Viewed 14.7k times · Source

I'm using CSVHelper to read in lots of data

I'm wondering if it's possible to read the last n columns in and transpose them to a list

"Name","LastName","Attribute1","Attribute2","Attribute3"

And mould the data into something like this

public class Person
{
    public string FirstName { get; set; }
    public string LastName { get; set; }
    public IList<string> Attributes { get; set; }
}

I'm looking to do this in one step, I'm sure I could have an intermediate step where I put into an object with matching attribute properties but it would be nice to do it on a one-er

Answer

Neil picture Neil · Jun 28, 2013

This does the trick as a mapper.

public sealed class PersonMap : CsvClassMap<Person>
{
    private List<string> attributeColumns = 
        new List<string> { "Attribute1", "Attribute2", "Attribute3" };

    public override void CreateMap()
    {
        Map(m => m.FirstName).Name("FirstName").Index(0);
        Map(m => m.LastName).Name("LastName").Index(1);
        Map(m => m.Attributes).ConvertUsing(row =>
            attributeColumns
                .Select(column => row.GetField<string>(column))
                .Where(value => String.IsNullOrWhiteSpace(value) == false)
            );
    }
}

Then you just need something like this

using (var reader = new CsvReader(new StreamReader(filePath)))
{
    reader.Configuration.RegisterClassMap<PersonMap>();
    while (reader.Read())
    {
        var card = reader.GetRecord<Person>();
    }
}