C# 实现汉字首字母提取与字符串排序

    /// <summary>
    /// 获取单个汉字的首写拼音字母
    /// </summary>
    /// <param name="cn"></param>
    /// <returns></returns>
    public static string getSpell(string cn)
    {
        #region
        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)
                {
                    return Encoding.Default.GetString(new byte[] { (byte)(65 + i) });
                }
            }
            return cn;
        }
        else return cn;
        #endregion
    }