C# 正规则表达式

获取括号里的内容
        public string GetRegexStr(string Str, string Symbol1, string Symbol2, bool needSymbol)
        {
            char A = Symbol1.ToCharArray()[0];
            char B = Symbol2.ToCharArray()[0];
            string pattern = string.Format(@"\{0}.*?\{1}", A, B);
            Regex regex = new Regex(pattern, RegexOptions.IgnoreCase);
            MatchCollection matches = regex.Matches(Str);
            StringBuilder sb = new StringBuilder();
            foreach (Match match in matches)
            {
                string value = "";
                if (!needSymbol)
                    value = match.Value.Trim(A, B);
                else
                    value = match.Value;
                sb.AppendLine(value);
            }
            return sb.ToString();
        }