CsvHelper ConvertUsing not changing output

Question

I\'m trying to use the ConvertUsing method of the CsvHelper library (v 2.4.0).

I\'ve read the documentation about ConvertUsing but can\'t get it to work

Answer 1

I had a similar need and this is what I made in order to modify the content before saving it into a csv file.

I have a custom class called StringNormalizer that implements CsvHelper.TypeConversion.ITypeConverter interface.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using CsvHelper.TypeConversion;

namespace MyNamespaceInHere {    
    public class StringNormalizer : ITypeConverter {
        public bool CanConvertFrom(Type type) {
            if (type == typeof(string)) return true;
            return false;
        }
        public bool CanConvertTo(Type type) {
            if (type == typeof(string)) return true;
            return false;
        }
        public object ConvertFromString(TypeConverterOptions options, string text) { return normalize(text); }
        public string ConvertToString(TypeConverterOptions options, object value) {
            if (value == null) return string.Empty;
            if (value.GetType() == typeof(string)) {
                string str = (string)value;
                return normalize(str);
            }
            return string.Empty;
        }
        public string normalize(string field) {
            // Do stuff in here and return normalized string
            return field + " just a sample";
        }
    }
}

Then in my main program where I have defined mappings I use it like this

public sealed class ConMap : CsvClassMap<Contact> {        
        public override void CreateMap() {
            Map(m => m.FirstName).Name("FirstName").TypeConverter<StringNormalizer>();
        }
    }

And thus all that is saved to csv are "run through" my string normalizer.

Answer 2

Currently ConvertUsing is only used when reading.

You can use a custom type converter if you want to customize the output. You also have some limited abilities through the type converter options.