网站开发技术手记－读取html标签内容

1。读取单标签内容：

    private string GetSingleTagValueByAttr(string inputstring,string tagName,string attrname,string key)
    {
        Regex reg = new Regex("<" + tagName + " [^<>]*>",RegexOptions.IgnoreCase);
        MatchCollection matchs = reg.Matches(inputstring);
        string result = "";
        foreach (Match match in matchs)
        {
            string matchValue = match.Value;
            Regex regValue = new Regex("content=\".*\"",RegexOptions.IgnoreCase);
            if (matchValue.ToLower().IndexOf(attrname + "=\"" + key + "\"") != -1)
            {
                if(regValue.IsMatch(matchValue))
                {
                    result = regValue.Match(matchValue).Value;
                    if (!string.IsNullOrEmpty(result))
                    {
                        result =result.ToLower().Replace("content=","").Replace("\"","");
                    }
                }
                return result;
            }
        }
        return "";
    }
使用举例：
string description=GetSingleTagValueByAttr(sourceHTML,“meta”,"name","description");
string keywords =GetSingleTagValueByAttr(sourceHTML,“meta”,"name","keywords");
改进：添加读取属性参数，目前只限定了读取的是meta的congtent的内容。
2。读取封闭标签的内容：
    private string GetFixTagContent(string inputstring,string tagName)
    {
        string leftTag = "<" + tagName + ">";
        string rightTag="</"+tagName+">";
        
        Regex reg = new Regex("<" +tagName+"[^<>]*>(.|\n)*" + rightTag,RegexOptions.IgnoreCase);
        return reg.Match(inputstring).Value.Replace(leftTag, "").Replace(rightTag, "");
    }
使用举例：
string title=GetFixTagContent(sourceHTML,"title");