asp.net 获取汉字首字母

        /// <summary>
        /// 获取一个简体中文字的拼音首字母
        /// </summary>
        /// <param name="cn">一个简体中文字</param>
        /// <returns>拼音首字母</returns>
        public string getSpell(string cnStr)
        {
            string en = "";
            List<string> list = new List<string>();
            if (cnStr.Length > 1)
            {
                for (int i = 0; i < cnStr.Length; i++)
                {
                    list.Add(cnStr.Substring(i, 1));
                }
            }
            foreach (string cn in list)
            {
                byte[] arrCN = Encoding.Default.GetBytes(cn);
                if (arrCN.Length > 1)
                {
                    int area = (short)arrCN[0];
                    int pos = (short)arrCN[1];
                    int code = (area << 8) + pos;
                    int[] areacode = { 45217, 45253, 45761, 46318, 46826, 47010, 47297, 47614, 48119, 48119, 49062, 49324, 49896, 50371, 50614, 50622, 50906, 51387, 51446, 52218, 52698, 52698, 52698, 52980, 53689, 54481 };
                    for (int i = 0; i < 26; i++)
                    {
                        int max = 55290;
                        if (i != 25) max = areacode[i + 1];
                        if (areacode[i] <= code && code < max)
                        {
                            en += Encoding.Default.GetString(new byte[] { (byte)(65 + i) });
                        }
                    }
                }
                else en += cn2;
            }
            return en;
        }