C#获取汉字的拼音的首拼

 public string getSpell(string cn)
        {
            string tempChar = "";
            char[] temp = cn.ToCharArray();
            for (int j = 0; j < temp.Length; j++)
            {
                byte[] arrCN = Encoding.Default.GetBytes(temp[j].ToString());
                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)
                        {
                            tempChar+= Encoding.Default.GetString(new byte[] { (byte)(65 + i) }).ToLower();
                        }
                    }
                    //tempChar += "?";
                }
                else
                     tempChar += cn;
            }
            return tempChar;
        
        }