How to write object that contains arrays using csvHelper?

Question

in C#/.net I deserialize a Api-request into a object. This object contains arrays, when i write it to file using csvHelper like this: https://joshclose.github.io/CsvHelper/examples/writing/write-class-objects/ The object is written to csv, but without the arrays.

My object which i serialize into, look like this:

public class MyMainObject
{
    public int Id { get; set; }
    public string Name { get; set; }
    public MyMissingArray[] data { get; set; }
}
public class MyMissingArray{
    public string id { get; set; }
    public string value { get; set; }
}

What is the best way to get these arrays into the csv file?

• Create ClassMap? : https://joshclose.github.io/CsvHelper/examples/configuration/class-maps/
• Create custom logic writing with foreach-loops : https://github.com/JoshClose/CsvHelper/issues/765
• Or is there a smother way to do this?
• How do i get the MyMissingArray into the final csvFile?

Answer 1

I think the easiest way will be to use Convert in a ClassMap. You can format the data how you want it.

void Main()
{
    var records = new List<MyMainObject>
    {
        new MyMainObject { 
            Id = 1, 
            Name = "Object1", 
            data = new MyMissingArray [] 
            {
                new MyMissingArray { id = "one", value = "value1" },
                new MyMissingArray { id = "two", value = "value2" },
                new MyMissingArray { id = "three", value = "value3" }
            }
        }
    };

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

public class MyMainObjectMap : ClassMap<MyMainObject>
{
    public MyMainObjectMap()
    {
        Map(x => x.Id);
        Map(x => x.Name);
        Map(x => x.data).Name("MyData").Convert(args =>
        {
            var flattenMissingArray = args.Value.data.Select(d => d.id + ":" + d.value);
            return string.Join(",", flattenMissingArray);
        });
    }
}

public class MyMainObject
{
    public int Id { get; set; }
    public string Name { get; set; }
    public MyMissingArray[] data { get; set; }
}
public class MyMissingArray
{
    public string id { get; set; }
    public string value { get; set; }
}