Three-tier .NET Application Utilizing Three ORM Technologies

using System;
using System.Collections.Generic;
using System.Text;
using s = System;
using System.Linq;
using gt=GlobalType;

namespace DomainUtil
{
	public class Participants
	{
		gt.IParticipant[] _arrParticipants;
		s.Collections.Generic.Dictionary<int, int> _dictOfIndexesByID;
		public Participants(IList<gt.IParticipant> lstParticipants)
		{
			IEnumerable<gt.IParticipant> sorted = lstParticipants.OrderBy(o=>o.ID);
			_arrParticipants = sorted.ToArray();
			_dictOfIndexesByID = new Dictionary<int,int>();
			int i = -1;
			foreach(gt.IParticipant aParticipant in sorted)
			{
				i++;
				_dictOfIndexesByID.Add(aParticipant.ID, i);
			}
		}
		public int IndexFromID(int iID)
		{
			return _dictOfIndexesByID[iID];
		}
		public string NameFromIndex(int iIndex)
		{
			return _arrParticipants[iIndex].Name;
		}
		public string NameFromID(int iID)
		{
			return NameFromIndex(IndexFromID(iID));
		}
		public int IDFromIndex(int iIndex)
		{
			return _arrParticipants[iIndex].ID;
		}

		public int Count
		{
			get
			{
				return _arrParticipants.Length;
			}
		}
		public int[] GetArrayOfIDs()
		{
			int[] arr = new int[_arrParticipants.Length];
			for (int i = 0; i < _arrParticipants.Length; i++)
			{
				arr[i] = _arrParticipants[i].ID;
			}
			return arr;
		}
		public gt.IParticipant[] GetArryOfObjects()
		{
			gt.IParticipant[] arr = new gt.IParticipant[_arrParticipants.Length];
			for (int i = 0; i < _arrParticipants.Length; i++)
			{
				arr[i] = _arrParticipants[i];
			}
			return arr;
		}
	}
}