using System;

using System.Collections.Generic;

using System.IO;

using System.Xml.Serialization;

​

public static class Program

{

    public static void Main(string[] args)

    {

        var order = new Order

        {

            Dates =

            {

                new OrderDate {Name = "20160810", Type = "received-date"},

                new OrderDate {Name = "20160810", Type = "required-date"}

            }

        };

​

        using (var writer = new StringWriter())

        {

            var serializer = new XmlSerializer(typeof(Order));

            serializer.Serialize(writer, order);

            Console.WriteLine(writer);

        }            

    }

}

​

[XmlRoot("order")]

public class Order

{

    [XmlElement("date")]

    public List<OrderDate> Dates { get; set; } = new List<OrderDate>();

}

​

public class OrderDate

{

    [XmlAttribute("type")]

    public string Type { get; set; }

​

    [XmlText]

    public string Name { get; set; }

}