Example of converting dictionary to IEnumerable.
using System;
using System.Collections;
using System.Collections.Generic;

namespace GetEnumerator
{
    class Program
    {
        static void Main(string[] args)
        {
            GetEnumeratorDict getEnumerator = new GetEnumeratorDict();

            foreach (KeyValuePair<int, string> getEnumeratorItem in getEnumerator)
            {
                Console.WriteLine($"getEnumeratorItem: {getEnumeratorItem}");
            }

            Console.WriteLine("Press any key ");
            Console.ReadKey();
        }
    }

    class GetEnumeratorDict : IEnumerable
    {
        readonly Dictionary<int, string> m_internalDictionary = new Dictionary<int, string>();

        public GetEnumeratorDict()
        {
            m_internalDictionary[1] = "test";
        }

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

    }
}
In code line:
IEnumerator IEnumerable.GetEnumerator()
{
	return m_internalDictionary.GetEnumerator();
}
You can implement your own OrderBy, something like I already explained hier. Difference between IEnumerator and IEnumerable you can read hier