JsonObjectAttribute force object serialization

[JsonObject]
public class Directory : IEnumerable<string>
{
    public string Name { get; set; }
    public IList<string> Files { get; set; }

    public Directory()
    {
        Files = new List<string>();
    }

    public IEnumerator<string> GetEnumerator()
    {
        return Files.GetEnumerator();
    }

    IEnumerator IEnumerable.GetEnumerator()
    {
        return GetEnumerator();
    }
}

Directory directory = new Directory
{
    Name = "My Documents",
    Files =
    {
        "ImportantLegalDocuments.docx",
        "WiseFinancalAdvice.xlsx"
    }
};

string json = JsonConvert.SerializeObject(directory, Formatting.Indented);

Console.WriteLine(json);
// {
//   "Name": "My Documents",
//   "Files": [
//     "ImportantLegalDocuments.docx",
//     "WiseFinancalAdvice.xlsx"
//   ]
// }