网页格式化排版代码，专用信息采集后的内容整理

        public static string ClearHtml(string content) {           
            Regex regex = new Regex("");
            //首先把p标签的属性去掉，只留

            regex = new Regex(@"", RegexOptions.IgnoreCase | RegexOptions.Singleline);
            content = regex.Replace(content, "
");

            //找到网页中的各种标签，留待后续处理
            regex = new Regex(@"<[/]*(?.*?)[\s>]", RegexOptions.Singleline | RegexOptions.IgnoreCase);
            List<string> labels = new List<string>();
            MatchCollection mclabels = regex.Matches(content);
            foreach (Match m in mclabels) {
                if(labels.Contains(m.Groups["txt"].Value) == false)
                    labels.Add(m.Groups["txt"].Value.ToLower());
            }
            //对各种标签进行替换，p、img、strong除外。br后面会进行单独处理
            foreach (string lable in labels) {
                if (lable=="p" || lable == "img" || lable=="strong" || lable=="br")
                    continue;
                regex = new Regex(@"<[\/]*" + lable + ".*?>", RegexOptions.IgnoreCase | RegexOptions.Singleline);
                content = regex.Replace(content, "");
            }
            MatchCollection mc = null;

            regex = new Regex(@".*?)['""].*?>", RegexOptions.Singleline | RegexOptions.IgnoreCase);
            mc = regex.Matches(content);
            foreach (Match m in mc) {
                content = content.Replace(m.Value,"");
            }

            Regex r = new Regex(@"", RegexOptions.IgnoreCase | RegexOptions.Singleline);
            content = r.Replace(content, "\r\n");
            r = new Regex(@"[\r\n\t]", RegexOptions.IgnoreCase | RegexOptions.Singleline);
            content = r.Replace(content, "
");
            content = content.Trim();
            if (content.StartsWith("") == true)
                content = content.Substring(4);
            if (content.EndsWith("
") == true)
                content = content.Remove(content.Length - 3);

            //替换段前空格开始
            regex = new Regex(@"
\s* ", RegexOptions.IgnoreCase | RegexOptions.Singleline);
            while (regex.IsMatch(content))
            {
                content = regex.Replace(content, @"
");
            }
            regex = new Regex(@"
\s+", RegexOptions.IgnoreCase | RegexOptions.Singleline);
            while (regex.IsMatch(content))
            {
                content = regex.Replace(content, @"
");
            }
            regex = new Regex(@"
　+", RegexOptions.IgnoreCase | RegexOptions.Singleline);
            while (regex.IsMatch(content))
            {
                content = regex.Replace(content, @"
");
            }
            //替换段前空格结束

            //替换p标签空嵌套的情况
            regex = new Regex(@"
\s*?
", RegexOptions.Singleline | RegexOptions.IgnoreCase);
            while (regex.IsMatch(content))
                content = regex.Replace(content, "
");
            regex = new Regex(@"<\/p>\s*?<\/p>", RegexOptions.Singleline | RegexOptions.IgnoreCase);
            while (regex.IsMatch(content))
                content = regex.Replace(content, @"");

            //替换p标签内容为空的情况
            regex = new Regex(@"
(?.*?)", RegexOptions.Singleline | RegexOptions.IgnoreCase);
            mc = regex.Matches(content);
            foreach (Match m in mc) {
                string value = m.Groups["txt"].Value;
                value = value.Replace(" ", "").Trim();
                if (string.IsNullOrEmpty(value) == true)
                    content = content.Replace(m.Value,"");
            }

            //段首加空格
            content = content.Replace("
", "
　　");

            return content;
        }

剔除了除p、img、strong之外的其他标签，对p、img的各种属性也进行了清除，专门用于生成干净的网页正文，可用于信息采集后的内容整理和格式化排版。自用代码，算法效率可能不高，但是足以满足目前需求了。