using System;

using System.Xml;

using System.Xml.Linq;

using HtmlAgilityPack;

public class Program

{

    public static void Main()

    {

        var html = @"<div>

    <div class='bla'>

      <p>Some text1</p>

    </div>

    <div class='bla'>

      <p>Some text2</p>

    </div>

</div>";

        var doc = new HtmlDocument();

        doc.LoadHtml(html);

        var nodes = doc.DocumentNode.SelectNodes("//div[@class='bla']");

        foreach(HtmlNode node in nodes)

        {

            Console.WriteLine(node.OuterHtml);

            Console.WriteLine();

        }

    }

}