闭合HTML标签和添加开始HTML标签

//基本想要得功能实现了，但在添加的标签顺序还有点问题 

 

#region 闭合HTML代码
        public string CloseHTML(string str)
        {
            string[] HtmlTag = new string[] { "ul", "font", "b", "u", "i", "a", "h1", "h2", "h3", "h4", "h5", "h6", "tr", "td", "span", "div", "table", "p" };
            for (int i = 0; i < HtmlTag.Length; i++)
            {
                int OpenNum = 0, CloseNum = 0;
                Regex re = new Regex("\\<" + HtmlTag[i] + "( [^\\<\\>]+|)\\>", RegexOptions.IgnoreCase);
                MatchCollection m = re.Matches(str);
                if (m != null)
                {
                    OpenNum = m.Count;
                }
                re = new Regex("\\<\\/" + HtmlTag[i] + "\\>", RegexOptions.IgnoreCase);
                m = re.Matches(str);
                if (m != null)
                {
                    CloseNum = m.Count;
                }

                for (int j = 0; j < OpenNum - CloseNum; j++)
                {
                    str += "</" + HtmlTag[i] + ">";
                }
            }
            return str;
        }
        #endregion

        #region 添加开始HTML代码
        public string OpenHTML(string str)
        {
            string[] HtmlTag = new string[] { "ul", "font", "b", "u", "i", "a", "h1", "h2", "h3", "h4", "h5", "h6", "tr", "td", "span", "div", "table", "p" };
            for (int i = 0; i < HtmlTag.Length; i++)
            {
                int OpenNum = 0, CloseNum = 0;
                Regex re = new Regex("\\<\\/" + HtmlTag[i] + "\\>", RegexOptions.IgnoreCase);
                MatchCollection m = re.Matches(str);
                if (m != null)
                {
                    OpenNum = m.Count;
                }
                re = new Regex("\\<" + HtmlTag[i] + "( [^\\<\\>]+|)\\>", RegexOptions.IgnoreCase);
                m = re.Matches(str);
                if (m != null)
                {
                    CloseNum = m.Count;
                }

                for (int j = 0; j < OpenNum - CloseNum; j++)
                {
                    str = "<" + HtmlTag[i] + ">" + str;
                }
            }
            return str;
        }
        #endregion