/// <summary>

        /// 根据html文本返回url地址集合

        /// </summary>

        /// <param name="sHtmlText"></param>

        /// <returns></returns>

        private List<string> GetImgUrlByHtmlText(string sHtmlText)

        {

            // 定义正则表达式用来匹配 img 标签

            Regex regImg = new Regex(@"<img\b[^<>]*?\bsrc[\s\t\r\n]*=[\s\t\r\n]*[""']?[\s\t\r\n]*(?<imgUrl>[^\s\t\r\n""'<>]*)[^<>]*?/?[\s\t\r\n]*>", RegexOptions.IgnoreCase);

            // 搜索匹配的字符串

            MatchCollection matches = regImg.Matches(sHtmlText);

            List<string> sUrlList = new List<string>();

            // 取得匹配项列表

            foreach (Match match in matches)

            {

                if (match.Groups["imgUrl"].Value != "")

                {

                    sUrlList.Add(match.Groups["imgUrl"].Value);

                }

            }

            // 定义正则表达式用来匹配 table 标签

            Regex regTable = new Regex(@"<(table|tr|td)\b[^<>]*?\bbackground[\s\t\r\n]*=[\s\t\r\n]*[""']?[\s\t\r\n]*(?<backgroundUrl>[^\s\t\r\n""'<>]*)[^<>]*?/?[\s\t\r\n]*>", RegexOptions.IgnoreCase);

            MatchCollection matchesTable = regTable.Matches(sHtmlText);

            // 取得匹配项列表

            foreach (Match match in matchesTable)

            {

                if (match.Groups["backgroundUrl"].Value != "")

                {

                    sUrlList.Add(match.Groups["backgroundUrl"].Value);

                }

            }

            return sUrlList;

        }