截取开始字符串 结束字符串的中间字符串并返回

  /// <summary>
        /// 指定开始字符串和结束字符串,截取中间的字符
        /// </summary>
        /// <param name="str">要截取的字符串</param>
        /// <param name="s">开始字符串</param>
        /// <param name="e">结束字符串</param>
        /// <returns></returns>
        public static string GetValue(string str, string s, string e)
        {
              Regex rg = new Regex("(?<=(" + s + "))[.\s\S]*?(?=(" + e + "))", RegexOptions.Multiline | RegexOptions.Singleline);
            return rg.Match(str).Value;
        }