using System;

using System.Collections.Generic;

using System.Xml;

using System.Xml.Serialization;

​

public class Program

{

    static void Main()

    {

​

        var obj = new Connection

        {

            SourceId = 0,

            TargetId = 1,

            ExtraParameters =

            {

                new ExtraParameter

                {

                    Input = 0,

                    Output = 1,

                    Enabled = true

                },

                new ExtraParameter

                {

                    Input = 1,

                    Output = 0,

                    Enabled = true

                }

            }

        };

​

        var settings = new XmlWriterSettings

        {

            Indent = true

        };

​

        using var writer = XmlWriter.Create(Console.Out, settings);

​

        new XmlSerializer(typeof(Connection)).Serialize(writer, obj);

    }

​

    public class Connection

    {

        public int SourceId { get; set; }

        public int TargetId { get; set; }

​

        [XmlElement("ExtraParameter")] 

        public List<ExtraParameter> ExtraParameters { get; } = new();

    }

​

    public class ExtraParameter

    {

        public int Input { get; set; }

        public int Output { get; set; }

        public bool Enabled { get; set; }

    }

}