public static string ReplaceHtmlTag(string html, int length = 0){    string strText = System.Text.RegularExpressions.Regex.Replace(html, "<[^>]+>", "");    strText = System.Text.RegularExpressions.Regex.Replace(strText, "&[^;]+;", "");    if (length > 0  && strText.Length > length)        return strText.Substring(0, length);    return strText;}