using System;

using System.Xml;

using System.Xml.XPath;

using System.Linq;

using HtmlAgilityPack;

public class Program

{

    public static void Main()

    {

        var link = "http://www.forexfactory.com/calendar.php?day=aug7.2015";

        var doc = new HtmlWeb().Load(link);

        //doc.Save("test.html");

        var findclasses = doc.DocumentNode.Descendants("div").Where(d =>

                                                                    d.Attributes.Contains("class") && d.GetAttributeValue("id", "").Contains("flex"));

        //var findclasses = doc.DocumentNode.Descendants("div").Where(d =>

        //         d.Attributes.Contains("class") && d.Attributes["id"].Value.Contains("flex"));

        foreach (var d in findclasses)

        {

            Console.WriteLine("{0}, {1}", d.Name, d.GetAttributeValue("id", ""));

        }

    }

}