C# - sort a list by some arbitrary sort order (i.e. not a "typical" sort order).

gistfile1.cs

// You can paste this code into IDEone (http://ideone.com) and run it.  For some reason, I can never remember how to do this.
// Therefore, I've made this Gist.  There's probably a million smarter ways to handle this situation, but this one seems to
// work just fine.
using System;
using System.Collections.Generic;
using System.Linq;

public class Test
{
	public static void Main()
	{
		// A collection of photos with some sort of caption.  Type describes
		// if the photo is Main, Inside or Outside.
		var photos = new [] {
			new { name = "first inside", type = "i" },
			new { name = "second inside", type = "i" },
			new { name = "I should be first", type = "m" },
			new { name = "third inside", type = "i" },
			new { name = "first outside", type = "o" },
			new { name = "second outside", type = "o" },
			new { name = "fourth inside", type = "i" }
		};
		
		// Describe the desired sort order - Main should be first,
		// then Outside photos, finally Inside photos.
		var sortOrder = new Dictionary<string, byte>() {
			{ "m", 0 }, // Main
      			{ "o", 1 }, // Outside
      			{ "i", 2 } // Inside
		};
		
		// Sort the photos by the specified sort order.
		var sortedPhotos = photos.OrderBy(x => sortOrder[x.type]);
		
		// View the results.
		foreach (var p in sortedPhotos)
		{
			Console.WriteLine(p.name);
		}
	}
}

// Output:
// I should be first
// first outside
// second outside
// first inside
// second inside
// third inside
// fourth inside