c#转义字符串中的所有正则特殊字符方法示例

/// <summary>
        /// 转义字符串中所有正则特殊字符
        /// </summary>
        /// <param name="input">传入字符串</param>
        /// <returns></returns>
        string filterstring(string input)
        {
            input = input.replace("\\", "\\\\");//先替换“\”，不然后面会因为替换出现其他的“\”

            regex r = new regex("[\\*\\.\\?\\+\\$\\^\\[\\]\\(\\)\\{\\}\\|\\/]");
            matchcollection ms = r.matches(input);
            list<string> list = new list<string>();
            foreach (match item in ms)
            {
                if (list.contains(item.value))
                    continue;
                input = input.replace(item.value, "\\" + item.value);
                list.add(item.value);
            }
            return input;
        }