TextBox 超链接替换成HTML超链接形式

            string tent = this.TextBox_info.Text.Replace("<", "&lt;").Replace(">", "&gt;").Replace(" ", "&nbsp;&nbsp;&nbsp;&nbsp;").Trim().Replace("\n", "<br/>");
            Regex regex = new Regex(@"(?:https?://|www\.)(?:[\w-]+\.)+[\w-]+(?:/[\w- ./?%&=]*)?", RegexOptions.ECMAScript);
            MatchCollection mc = regex.Matches(tent);
            string text = "";
            List<string> list = new List<string>();
            foreach (Match m in mc)
            {
                list.Add(m.ToString());
            }
            for (int i = 0; i < list.Count; i++)
            {
                for (int j = i + 1; j < list.Count; j++)
                {
                    if (list[i] == list[j])
                    {
                        list.Remove(list[j]);
           &