取得汉字拼音首字母

//-----------------取得汉字拼音首字母---------
用getSpells(string input)
 public string getSpells(string input)
  {
   int len = input.Length;
   string reVal = "";
   for(int i=0;i<len;i++)
   {
    reVal += getSpell(input.Substring(i,1));
   }
   return reVal;
  }

   public string getSpell(string cn)
  {
   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 "?";
   }
   else return cn;
  }