.net抓取网页内容回来如何用正则匹配出来

.net抓取网页内容回来怎么用正则匹配出来
.net抓取网页内容回来怎么用正则匹配出来 内容抓回来了 我需要用正则怎么匹配出来里面的内容 求大神

主要代码如下：
try
            {
                HttpWebRequest request = (HttpWebRequest)WebRequest.Create(Capture);
                //HttpWebRequest请求
                request.Headers.Set("Pragma", "no-cache");

                HttpWebResponse response = (HttpWebResponse)request.GetResponse();

                Stream streamReceive = response.GetResponseStream();

                Encoding encoding = Encoding.GetEncoding("GB2312");
                //StreamReader reader = new StreamReader(response.GetResponseStream(), Encoding.GetEncoding("gb2312")); 

                StreamReader streamReader = new StreamReader(streamReceive, encoding);

                strResult = streamReader.ReadToEnd(); //strResult是抓取出来的源代码 我需要匹配

            }
                
            catch
            {

            }
            return;

Regex需要using System.Text.RegularExpressions;