老调重弹，求一正则！该如何解决_ASP.NET

老调重弹，求一正则！

HTML code

                        <ul class="vv41Table">                         <li class='vv4TableDIV1' >                        <span class="vv41A"><a href="../ddddd/sss" target="_blank">********</a></span></li>                         <li class='vv4TableDIV1' >                        <span class="vv41A"><a href="../ddddd/sss" target="_blank">********</a></span></li>                         <li class='vv4TableDIV1' >                        <span class="vv41A"><a href="../ddddd/sss" target="_blank">********</a></span></li>                         <li class='vv4TableDIV1' >                        <span class="vv41A"><a href="../ddddd/sss" target="_blank">********</a></span></li>                        </ul>

页面里有这么一个列表，匹配列表里面的a标签！ul外面也会有a标签，但是不匹配，只匹配<ul class="vv41Table">下的a标签

------解决方案--------------------------------------------------------

C# code

        string s = File.ReadAllText(Server.MapPath("~/test.txt"));        MatchCollection matches=Regex.Matches(s, @"(?is)(?<=<ul[^>]+class=""vv41Table""[^>]*>.*?)<a[^>]+>.*?</a>(?=.*?</ul>)");        foreach (Match match in matches)            Response.Write(Server.HtmlEncode(match.Value) + "<br/>");
------解决方案--------------------------------------------------------
 <ul class="vv41Table">
                        <li class='vv4TableDIV1' >
                       <span class="vv41A"><a href="../ddddd/sss" target="_blank">********</a></span></li>
                        <li class='vv4TableDIV1' >
                       <span class="vv41A"><a href="../ddddd/sss" target="_blank">********</a></span></li>
                        <li class='vv4TableDIV1' >
                       <span class="vv41A"><a href="../ddddd/sss" target="_blank">********</a></span></li>
                        <li class='vv4TableDIV1' >
                       <span class="vv41A"><a href="../ddddd/sss" target="_blank">********</a></span></li>
                       </ul>
  <ul class="vv41Table1">
                        <li class='vv4TableDIV1' >
                       <span class="vv41A"><a href="../ddddd/sss" target="_blank">********</a></span></li>
                        <li class='vv4TableDIV1' >
                       <span class="vv41A"><a href="../ddddd/sss" target="_blank">********</a></span></li>
                        <li class='vv4TableDIV1' >
                       <span class="vv41A"><a href="../ddddd/sss" target="_blank">********</a></span></li>
                        <li class='vv4TableDIV1' >
                       <span class="vv41A"><a href="../ddddd/sss" target="_blank">********</a></span></li>
                       </ul>
------------------------------------
这样结果不正确
------解决方案--------------------------------------------------------