CSVHelper writing fixed lenght field

Question

I've been writing csv files since now composing strings, but looking for a more structured solution I came a across to csvhelper. It's clear to me how to read data and perform type conversion, but what about when writing a csv file to specify the field lenght? suppose I've a field that starts from 0 and takes 4 char lenght... how can I specify this? I've not found and attribute or so....

Thanks

Answer 1

You could use a custom type converter to specify a fixed width.

void Main()
{
    var records = new List<Foo>
    {
        new Foo { Id = 1, Name = "one" },
    };

    using (var writer = new StreamWriter("path\\to\\file.csv"))
    using (var csv = new CsvWriter(writer))
    {
        csv.Configuration.RegisterClassMap<FooMap>();
        csv.WriteRecords(records);
    }
}

public class Foo
{
    public int Id { get; set; }
    public string Name { get; set; }
}

public sealed class FooMap : ClassMap<Foo>
{
    public FooMap()
    {
        AutoMap();
        Map(m => m.Id).TypeConverter<FixedWidthOutput>();
    }
}

public class FixedWidthOutput : Int32Converter
{
    public override string ConvertToString(object value, IWriterRow row, MemberMapData memberMapData)
    {
        return value.ToString().PadLeft(4, '0');
    }
}