Improving LINQ Code Reusability: Select Method

namespace Mapper
{
	using System;
	using System.Collections.Generic;
	using System.Linq;
	using System.Text;
	using DataContracts;
	using Domain;


	/// <summary>
	/// Ojbect mapper
	/// </summary>
	public class ObjectMapper : IObjectMapper
	{
		private Dictionary<Type, Func<object, object>> Mappers = new Dictionary<Type, Func<object, object>>
		{
			{ typeof(Tuple<Album, AlbumDetail>), CreateAlbumDetail },
			{ typeof(Tuple<Album, AlbumSummary>), CreateAlbumSummary }

			// more mappings here
			// ....
		};


		/// <summary>
		/// Converts an object of type <c>TSource</c> to an object
		/// of type <c>TDestination</c>
		/// </summary>
		/// <typeparam name="TSource">The type of the source.</typeparam>
		/// <typeparam name="TDestination">The type of the destination.</typeparam>
		/// <param name="source">The source object to convert.</param>
		/// <returns>
		/// The converted object
		/// </returns>
		public TDestination Map<TSource, TDestination>(TSource source)
		{
			if(source == null)
				return default(TDestination);

			Func<object, object> mapper = null;
			Type key = typeof(Tuple<TSource, TDestination>);

			if(Mappers.TryGetValue(key, out mapper))
			{
				var newObject = mapper(source);
				return (TDestination) newObject;
			}

			string errorMessage = string.Format("Could not find mapping for requested types (Source: {0}, Destination: {1})",
											typeof(TSource).FullName, typeof(TDestination).FullName);
			
			throw new InvalidOperationException(errorMessage);
		}


		private static object CreateAlbumDetail(object source)
		{
			var album = source as Album;

			return new AlbumDetail {
				AlbumId = album.AlbumId,
				Price = album.Price,
				Title = album.Title,

				ArtistId = album.ArtistId,
				GenreId = album.GenreId,
				ArtistName = (album.Artist == null) ? null : album.Artist.Name,
				GenreName = (album.Genre == null) ? null : album.Genre.Name
			};
		}

		private static object CreateAlbumSummary(object source)
		{
			var album = source as Album;

			return new AlbumSummary {
				AlbumId = album.AlbumId,
				Title = album.Title,
				
				ArtistName = (album.Artist == null) ? null : album.Artist.Name
			};
		}
	}
}