解决C#识别变量定义的正则表达式

 Collection collection = new Collection();
            collection.Coding = "GB2312";
            string HtmlCode = collection.ReaderHTMLCode("http://www.qqtu88.com/qqjq/index.html");
            string pageurl = "http://www.qqtu88.com/qqjq/QQkongjianjishu/2011/0806/27479.html";
            string pReg = "\\d+";
            string Link_str = "";
            Uri u = new Uri(pageurl);
            pageurl = pageurl.ToLower().Replace("http://", "").Replace(u.Host.ToString().ToLower(), "");
            pageurl = Regex.Replace(pageurl, pReg, "\\\\d+");
            pageurl = pageurl.Replace(".", "\\\\.");
            Label1.Text = pageurl;
            MatchCollection m = Regex.Matches(HtmlCode.ToLower(), Regex.(pageurl));
            for (int c = 0; c <= m.Count - 1; c++)
            {
                string strNew = m[c].ToString();
                // 过滤重复的URL 
                if (Link_str.IndexOf(strNew) == -1)
                {
                    Link_str += "http://" + u.Host + strNew + ",";
                }
            }
            TextBox1.Text = Link_str;

最主要的是Regex.这个函数可以对变量中的转义字符进行转义

下面方法也可以

 Collection collection = new Collection();
            collection.Coding = "GB2312";
            string HtmlCode = collection.ReaderHTMLCode("http://www.qqtu88.com/qqjq/index.html");
            string pageurl = "http://www.qqtu88.com/qqjq/QQkongjianjishu/2011/0806/27479.html";
            string pReg = "\\d+";
            string Link_str = "";
            Uri u = new Uri(pageurl);
            pageurl = pageurl.ToLower().Replace("http://", "").Replace(u.Host.ToString().ToLower(), "");
            pageurl = Regex.Replace(pageurl, pReg, "\\d+");
            pageurl = pageurl.Replace(".", "\\.");
            Label1.Text = pageurl;
            Regex r = new Regex(pageurl , RegexOptions.IgnoreCase);
            MatchCollection m = r.Matches(HtmlCode.ToLower());
            for (int c = 0; c <= m.Count - 1; c++)
            {
                string strNew = m[c].ToString();
                // 过滤重复的URL 
                if (Link_str.IndexOf(strNew) == -1)
                {
                    Link_str += "http://" + u.Host + strNew + ",";
                }
            }
            TextBox1.Text = Link_str;