ASP.NET如何检索页面上的空标签列表？

using System.Text.RegularExpressions;

string html = "<div><p></p><p></p><p>Hello World</p></div>";

Regex regex = new Regex(@"<[^>]*></[^>]*>");

MatchCollection matches = regex.Matches(html);

foreach (Match match in matches)
{
    Console.WriteLine(match.Value);
}

using HtmlAgilityPack;

string html = "<div><p></p><p></p><p>Hello World</p></div>";

HtmlDocument document = new HtmlDocument();
document.LoadHtml(html);

var emptyTags = document.DocumentNode.Descendants()
    .Where(node => node.ChildNodes.Count == 0 && node.InnerHtml.Trim() == string.Empty);

foreach (var tag in emptyTags)
{
    Console.WriteLine(tag.OuterHtml);
}

using System.Xml.XPath;

string html = "<div><p></p><p></p><p>Hello World</p></div>";

XPathDocument document = new XPathDocument(new StringReader(html));
XPathNavigator navigator = document.CreateNavigator();

XPathNodeIterator iterator = navigator.Select("//*[not(*) and not(normalize-space())]");

while (iterator.MoveNext())
{
    Console.WriteLine(iterator.Current.OuterXml);
}