获取汉字首字母

/// <summary>
        /// 得到一个汉字的拼音第一个字母，如果是一个英文字母则直接返回大写字母
        /// </summary>
        /// <param name="CnChar">单个汉字</param>
        /// <returns>单个大写字母</returns>
        private static string GetCharSpellCode(string CnChar)
        {
            long iCnChar;
            byte[] ZW = System.Text.Encoding.Default.GetBytes(CnChar);

            //如果是字母，则直接返回
            if (ZW.Length == 1)
                return CnChar.ToUpper();
            else
            {
                int i1 = (short)(ZW[0]);
                int i2 = (short)(ZW[1]);
                iCnChar = i1 * 256 + i2;
            }

            // iCnChar match the constant
            if ((iCnChar >= 45217) && (iCnChar <= 45252))
                return "A";
            else if ((iCnChar >= 45253) && (iCnChar <= 45760))
                return "B";
            else if ((iCnChar >= 45761) && (iCnChar <= 46317))
                return "C";
            else if ((iCnChar >= 46318) && (iCnChar <= 46825))
                return "D";
            else if ((iCnChar >= 46826) && (iCnChar <= 47009))
                return "E";
            else if ((iCnChar >= 47010) && (iCnChar <= 47296))
                return "F";
            else if ((iCnChar >= 47297) && (iCnChar <= 47613))
                return "G";
            else if ((iCnChar >= 47614) && (iCnChar <= 48118))
                return "H";
            else if ((iCnChar >= 48119) && (iCnChar <= 49061))
                return "J";
            else if ((iCnChar >= 49062) && (iCnChar <= 49323))
                return "K";
            else if ((iCnChar >= 49324) && (iCnChar <= 49895))
                return "L";
            else if ((iCnChar >= 49896) && (iCnChar <= 50370))
                return "M";
            else if ((iCnChar >= 50371) && (iCnChar <= 50613))
                return "N";
            else if ((iCnChar >= 50614) && (iCnChar <= 50621))
                return "O";
            else if ((iCnChar >= 50622) && (iCnChar <= 50905))
                return "P";
            else if ((iCnChar >= 50906) && (iCnChar <= 51386))
                return "Q";
            else if ((iCnChar >= 51387) && (iCnChar <= 51445))
                return "R";
            else if ((iCnChar >= 51446) && (iCnChar <= 52217))
                return "S";
            else if ((iCnChar >= 52218) && (iCnChar <= 52697))
                return "T";
            else if ((iCnChar >= 52698) && (iCnChar <= 52979))
                return "W";
            else if ((iCnChar >= 52980) && (iCnChar <= 53640))
                return "X";
            else if ((iCnChar >= 53689) && (iCnChar <= 54480))
                return "Y";
            else if ((iCnChar >= 54481) && (iCnChar <= 55289))
                return "Z";
            else
                return ("?");
        }