public class BlogPostStateMachine
  {
    // .... مثال قسمت دوم
  }

public interface IFruit
{
    static abstract bool HasSeeds { get; }
}

public record Watermelon : IFruit
{
    public static bool HasSeeds => false;
}

public record Apple : IFruit
{
    public static bool HasSeeds => true;
}

void HasSeeds<T>(T fruit) where T: IFruit {
    Console.WriteLine(T.HasSeeds);
}

HasSeeds(new Apple());
HasSeeds(new Watermelon());

using System;
using System.Linq;
using System.IO;

namespace LINQtoDir
{
   class Program
   {
       static void Main(string[] args)
       {
           var query = from f in new DirectoryInfo(@"C:\Documents and Settings\vahid\My Documents\My Pictures")
                                 .GetFiles("*.*", SearchOption.AllDirectories)
                       where f.Extension.ToLower() == ".png" || f.Extension.ToLower() == ".jpg"
                       orderby f.LastAccessTime
                       select new
                       {
                           DateLastModified = f.LastWriteTime,
                           Extension = f.Extension,
                           Size = f.Length,
                           FileName = f.Name
                       };

           foreach (var file in query)
               Console.WriteLine(file.FileName);

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

    <script src="jquery-1.8.0.min.js" type="text/javascript"></script>
    <script type="text/javascript" src="https://www.google.com/jsapi"></script>
    <script type="text/javascript">

        google.load("feeds", "1");

        function initializeda() {
            var feed = new google.feeds.Feed("http://www.drupaleasy.ir/rss.xml");
            feed.setNumEntries(5);
            feed.setResultFormat(google.feeds.Feed.JSON_FORMAT);
            feed.load(function (result) {
                if (!result.error) {
                    for (var i = 0; i < result.feed.entries.length; i++) {
                        var entry = result.feed.entries[i];
                        $('#drupaleasy ul').append('<li><a href="' + entry.link + '">' + entry.title + '</a></li>');
                    }
                }
            });
        }

google.setOnLoadCallback(initializeda);
    </script>

<script type="text/javascript" src="https://www.google.com/jsapi"></script>

google.load("feeds", "1");

var feed = new google.feeds.Feed("http://www.drupaleasy.ir/rss.xml");

feed.setNumEntries(5);
feed.setResultFormat(google.feeds.Feed.JSON_FORMAT);

            feed.load(function (result) {
                if (!result.error) {
                    for (var i = 0; i < result.feed.entries.length; i++) {
                        var entry = result.feed.entries[i];
                        $('#drupaleasy ul').append('<li><a href="' + entry.link + '">' + entry.title + '</a></li>');
                    }
                }
            });

        .feeds
        {
            float: right;
            background-color: rgba(234, 242, 243, 0.73);
            margin: 5px;
            border-radius: 20px;
            padding: 8px;
            width: 293px;
            height: 217px;
            border: 1px solid #293883;
        }

        #drupaleasy ul
        {
            list-style-image: url("img/drupal.png");
        }