How to get div class name using HtmlAgilityPack in ASP.Net

// Where node is a HtmlNode instance
string[] cssClasses = node.Attributes["class"] != null
                                      ? node.Attributes["class"].Value.Split(new[] {" "}, StringSplitOptions.RemoveEmptyEntries)
                                      : new string[0];

foreach(string cssClass in cssClasses)
{
    // Do whatever you need to do with the CSS class
}