asp.net 正则 例子

using System.Text.RegularExpressions; //正则

string strHtml = " </ul> <div id=\"photo-tags\"> <h3 id=\"tags-title\">Tags in this photo: </h3>

<ul id='tags'>

<li> <a href='/user/669345/tags/Belgium'>Belgium </a> </li>

<li> <a href='/user/669345/tags/Belgien'>Belgien </a> </li>

<li> <a href='/user/669345/tags/Urlaub'>Urlaub </a> </li>

<li> <a href='/user/669345/tags/Holidays'>Holidays </a> </li>

<li> <a href='/user/669345/tags/Vakanties'>Vakanties </a> </li>

<li> <a href='/user/669345/tags/CenterParcs'>CenterParcs </a> </li>

<li> <a href='/user/669345/tags/10 000 000'>10 000 000 </a> </li>

</ul> </div> <div id=\"photo-info\">";

TextBox1.Text = "" + strHtml + "";

      Regex re = new Regex("(?<=<li> <a href='/user/[^>]*/tags/[^>]*>).*?(?= </a> </li>)");

      if (re.IsMatch(strHtml))
      {
          MatchCollection mc = re.Matches(strHtml);
          foreach (Match ma in mc)
          {
              for (int i = 0; i < ma.Groups.Count; i++)
              {
                  TextBox2.Text += ma.Groups[i].Value + " ";
              }
              TextBox2.Text += "\n";
          }
      }
      else
      {
          TextBox2.Text = "no";
      }

结果：

Belgium

Belgien

Urlaub

Holidays

Vakanties

CenterParcs

10 000 000

/// <summary>

/// 从文章内容中获取第一张图片，用作文章缩略图

/// </summary>

/// <param name="articleContent"></param>

/// <returns></returns>

public static string GetImageUrlFromArticle(string articleContent)

{

    Regex r = new Regex(@"<IMG[^>]+src=\s*(?:'(?<src>[^']+)'|""(?<src>[^""]+)""|(?<src>[^>\s]+))\s*[^>]*>", RegexOptions.IgnoreCase);

    MatchCollection mc = r.Matches(articleContent);

    if (mc.Count != 0)

    {

        return mc[0].Groups["src"].Value.ToLower();

    }

    else

    {

        return "";

    }

}