using System;

using System.Reflection;

​

[System.AttributeUsage(System.AttributeTargets.Field)]

public class PrimaryKeySegmentAttribute : System.Attribute

{

    public readonly string Value;

    public PrimaryKeySegmentAttribute(string value)

    {

        Value = value;

    }

}

​

[System.AttributeUsage(System.AttributeTargets.Field)]

public class UrnSegmentAttribute : System.Attribute

{

    public readonly string Value;

    public UrnSegmentAttribute(string value)

    {

        Value = value;

    }

}

​

public enum ExchangeSegment

{

    [PrimaryKeySegment("FL")]

    File,

    Property,

    Address,

    [UrnSegment("contact-ref")]

    Contact

}

​

// Source: https://stackoverflow.com/a/40358579

public static class SegmentExtensionMethods

{

    public static string ToPrimaryKeySegment<T>(this T value)

        where T : IConvertible

    {

        if (!typeof(T).IsEnum)

        {

            throw new ArgumentException("T must be an enumerated type");

        }

​

        FieldInfo fieldInfo = value.GetType().GetField(value.ToString());

        if (fieldInfo == null)

            return null;

        var attribute = (PrimaryKeySegmentAttribute)fieldInfo.GetCustomAttribute(typeof(PrimaryKeySegmentAttribute));

        if (attribute == null)

        {

            return value.ToString();

        }

​

        return attribute.Value;

    }

​

    public static string ToUrnSegment<T>(this T value)

        where T : IConvertible

    {

        if (!typeof(T).IsEnum)

        {

            throw new ArgumentException("T must be an enumerated type");

        }

​

        FieldInfo fieldInfo = value.GetType().GetField(value.ToString());

        if (fieldInfo == null)

            return null;

        var attribute = (UrnSegmentAttribute)fieldInfo.GetCustomAttribute(typeof(UrnSegmentAttribute));

        if (attribute == null)

        {

            return value.ToString().ToLower();

        }

​

        return attribute.Value;

    }

}

​

public class Program

{

    public static void Main()

    {

        var segment = ExchangeSegment.File;

        Console.WriteLine("PK Segment is " + segment.ToPrimaryKeySegment());

        Console.WriteLine("UrnSegment is " + segment.ToUrnSegment());

        segment = ExchangeSegment.Contact;

        Console.WriteLine("Segment is " + segment.ToPrimaryKeySegment());

        Console.WriteLine("UrnSegment is " + segment.ToUrnSegment());

    }

}