正则表达式 取两字符中间的字符串（双向非贪婪模式）

        /// <summary>
        /// 获取某字符串中间的字符串，非贪婪模式
        /// </summary>
        /// <param name="input">全字符串</param>
        /// <param name="left">左边字符</param>
        /// <param name="right">右边字符</param>
        /// <returns></returns>
        public static List<string> GetCenterString(String input, String left, String right)
        {
            List<string> list = new List<string>();
            Regex reg = new Regex(left + "(((?!" + left + ").)+?)" + right);
            foreach (Match m in reg.Matches(input))
            {
                list.Add(m.Value);
            }

            return list;
        }

改进：添加参数是否包含左右字符

        /// <summary>
        /// 获取某字符串中间的字符串，非贪婪模式
        /// </summary>
        /// <param name="input">全字符串</param>
        /// <param name="left">左边字符</param>
        /// <param name="right">右边字符</param>
        /// <param name="isBorder">是否包含 left right 字符</param>
        /// <returns></returns>
        public static List<string> GetCenterString(String input, String left, String right, bool isBorder = true)
        {
            List<string> list = new List<string>();
            Regex reg = new Regex(left + "(((?!" + left + ").)+?)" + right);
            foreach (Match m in reg.Matches(input))
            {
                string value = m.Value;
                if (!isBorder)
                {
                    value = value.Substring(left.Length, value.Length - left.Length);
                    value = value.Substring(0, value.Length - right.Length);
                }
                list.Add(value);
            }

            return list;
        }

测试：

 string all = @"这是一段测试数据{{dasdasdas}}这是一段测试数据{{ddd}{这是一段测试数据{{dasd}";
            List<string> strList = StringPlus.GetCenterString(all, "{", "}");

输出结果：{dasdasdas}、{ddd}、{dasd}