public sealed class FilterHelper    {        private Regex r;        #region Singleton        private static readonly FilterHelper instance = new FilterHelper();        public static FilterHelper Instance { get { return instance; } }        private FilterHelper() { }        #endregion        private void ReadRex()        {            string path = AppDomain.CurrentDomain.BaseDirectory;            string textFile = path + "FilterSt.txt";            FileStream fs;            if (File.Exists(textFile))            {                fs = new FileStream(textFile, FileMode.Open, FileAccess.Read);                using (fs)                {                    ////TextRange text = new TextRange(richTextBox1.Document.ContentStart, richTextBox1.Document.ContentEnd);                    //text.Load(fs, DataFormats.Text);                    //创建一个容量4M的数组                    byte[] byteData = http://www.mamicode.com/new byte[fs.Length];                    //从文件中读取数据写入到数组中(数组对象，从第几个开始读，读多少个)                    //返回读取的文件内容真实字节数                    int length = fs.Read(byteData, 0, byteData.Length);                    //如果字节数大于0，则转码                    if (length > 0)                    {                        //将数组转以UTF-8字符集编码格式的字符串                        var filterst = ".*(" + Encoding.UTF8.GetString(byteData) + ").*";                        r=new Regex(@filterst);                    }                }            }            else            {                throw new FileNotFoundException("找不到屏蔽字库");            }        }        /// <summary>        /// 判断是否屏蔽        /// </summary>        /// <param name="input"></param>        /// <returns></returns>        public bool IsStFilter(string input)        {            if (string.IsNullOrEmpty(input))            {                throw new Exception("输入不能为空");            }            if (r == null)            {                ReadRex();            }            if (r.IsMatch(input))            {                return true;            }            else            {                return false;            }        }    }