/// <summary>
/// Description résumée de Rss
/// </summary>
public class Feeds
{
    /// <summary>
    /// Ecriture du flux RSS
    /// </summary>
    public static void Write()
    {
        String path = HttpContext.Current.Server.MapPath("...path.../blog.rss"); // Avec path : chemin du flux
        String url = String.Concat("...path.../fichier.aspx?id="); // Avec path et fichier pour désigner le fichier qui permetra d'avoir un lien vers la page du post

        XDocument document = new XDocument(
            new XDeclaration("1.0", "utf-8", null),
            new XElement("rss",
                new XElement("channel",
                    new XElement("title", "Nom du site"),
                    new XElement("link", "Url du site"),
                    new XElement("pubDate", Date2RFC822(DateTime.Now)),
                    new XElement("lastBuildDate", Date2RFC822(DateTime.Now)),
                        from p in new DataContext().Post.OrderByDescending(c => c.date_edition).Take(10)
                        select new XElement("item",
                            new XElement("guid", p.id_post.ToString()),
                            new XElement("pubDate", Date2RFC822(p.date_edition)),
                            new XElement("title", p.titre),
                            new XElement("description", p.texte),
                            new XElement("link", String.Concat(url, p.id_post.ToString()))
                            )
                    )
                ,
                new XAttribute("version", "2.0"))
            );

        //Stream d'écriture du fichier
        System.IO.TextWriter writer = new System.IO.StreamWriter(path, false, Encoding.Default);
        document.Save(writer);
        writer.Flush();
        writer.Close();
    }

    /// <summary>
    /// Formatage de date
    /// </summary>
    /// <param name="date"></param>
    /// <returns></returns>
    private static String Date2RFC822(DateTime date)
    {

        Int32 offset = TimeZone.CurrentTimeZone.GetUtcOffset(DateTime.Now).Hours;
        StringBuilder sb = new StringBuilder();

        sb.Append(date.ToString("ddd, dd MMM yyyy HH:mm:ss "));

        if (offset < 0)
        {
            sb.AppendFormat("-{0:00}00", offset * -1);
        }
        else if (offset == 0)
        {
            sb.Append("GMT");
        }
        else
        {
            sb.AppendFormat("+{0:00}00", offset);
        }

        return sb.ToString();

    }

}