Regex r = new Regex(@"(?is)(?<=id=""nbaVidRsltBody"")(?:(?!id=""nbaVidPagBtm"").)*(?=id=""nbaVidPagBtm"")");

Regex r = new Regex(@"(?is)(?<=id=""nbaVidRsltBody""[^>]+>).+?(?=id=""nbaVidPagBtm"")");

            Regex re = new Regex(@"<div\b[^>]*?id=""nbaVidRsltBody""[^>]*>([\s\S]*?)<div\b[^>]*?id=""nbaVidPagBtm""[^>]*>", RegexOptions.IgnoreCase);
            Match match = re.Match(str);
            if(match.Success)
            {
                Console.WriteLine(match.Groups[1].Value);
            }

------解决方案--------------------

@"(?is)(?<=<div id=""nbaVidRsltBody""[^>]*>).+?(?=<div id=""nbaVidPagBtm"">)"

------解决方案--------------------

楼主怎么知道你给的两个正则没效果，用什么测试的，要么是你的测试数据有问题，要么是你的测试工具或代码有问题，你给的正则是可以取到结果的

C# code
string test = @"图挂掉了，具体情况看下面

<div id=""nbaVidRsltBody"" style....>

....(这里还有很多内容)

<div id=""nbaVidPagBtm"">  ";
Regex r = new Regex(@"(?is)(?<=id=""nbaVidRsltBody""[^>]+>).*?(?=id=""nbaVidPagBtm"")"); 
MatchCollection mc = r.Matches(test);
foreach (Match m in mc)
{
    richTextBox2.Text += m.Value + "\n";
}
/*-----输出-----


....(这里还有很多内容)

<div 
*/

------解决方案--------------------

建立一个txt文档，内容如下：
HTML code

<div id="nbaVidRsltBody" style="visibility: visible; "> fdahslflkaslkashllfhads347r84<div id="nbaVidPagBtm"> 
<div id="nbaVidRsltBody" style="visibility: visible; ">1231<div id="nbaVidPagBtm"> 
<div id="nbaVidRsltBody" style="visibility: visible; ">dfs4<div id="nbaVidPagBtm"> 
<div id="nbaVidRsltBody" style="visibility: visible; "> f333ds<div id="nbaVidPagBtm"> 
<div id="nbaVidRsltBody" style="visibility: visible; "> fdse34434343<div id="nbaVidPagBtm">