How to get div by class in HtmlAgilityPack?

I'm following this tutorial, but I have a problem, I don't know how to get htmlNode by class name .

HtmlDocument htmlDoc = new HtmlAgilityPack.HtmlDocument();
htmlDoc.OptionFixNestedTags = true;
htmlDoc.LoadHtml(e.Result);
HtmlNode divContainer = htmlDoc.GetElementbyId("directoryItems");//My problem here,I want to get by class name html
if (divContainer != null)
{
     HtmlNodeCollection nodes = divContainer.SelectNodes("//table/tr");
     ....
}