将GB2312,GBK的汉字首字母查出来的程序代码

using System;

namespace ConsoleApplication3
{

//我编程时要用到查询测字拼音首字母的功能，于是从网上搜
//但发现大部分都是将汉字的内码转换成区位码，然后得出拼音的首字母
//这个方法好是好，只是许多GB2312编码以外的汉字查不到,于是我想了这个办法，我觉得代码很短，但很实用
//而且GBK字符集的汉字都能查，希望大家多提意见
    public class hzpy
    {
        public hzpy()
        {
            //
            // TODO: 在此处添加构造函数逻辑
            //
        }


        //返回给定字符串的单个字
        public String IndexCode(String IndexTxt)
        {
            String _Temp=null;
            for(int i=0;i<IndexTxt.Length;i++)
                _Temp = _Temp + GetOneIndex( IndexTxt.Substring(i,1) );
            return _Temp;
        }



        //得到单个字符的首字母
        private String GetOneIndex(String OneIndexTxt)
        {
        

            if(Convert.ToChar(OneIndexTxt)>=0 && Convert.ToChar(OneIndexTxt)<256)
                return OneIndexTxt;
            else
                return GetGbkX(OneIndexTxt);
        }



        //根据根据测字拼音排序得到首字母

        public string GetGbkX(string str)
        {
            if(str.CompareTo("吖")<0)
            {
                return str;
            }
            if(str.CompareTo("八")<0)
            {
                return "A";
            }

            if(str.CompareTo("嚓")<0)
            {
                return "B";
            }

            if(str.CompareTo("咑")<0)
            {
                return "C";
            }
            if(str.CompareTo("妸")<0)
            {
                return "D";
            }
            if(str.CompareTo("发")<0)
            {
                return "E";
            }
            if(str.CompareTo("旮")<0)
            {
                return "F";
            }
            if(str.CompareTo("铪")<0)
            {
                return "G";
            }
            if(str.CompareTo("讥")<0)
            {
                return "H";
            }
            if(str.CompareTo("咔")<0)
            {
                return "J";
            }
            if(str.CompareTo("垃")<0)
            {
                return "K";
            }
            if(str.CompareTo("嘸")<0)
            {
                return "L";
            }
            if(str.CompareTo("拏")<0)
            {
                return "M";
            }
            if(str.CompareTo("噢")<0)
            {
                return "N";
            }
            if(str.CompareTo("妑")<0)
            {
                return "O";
            }
            if(str.CompareTo("七")<0)
            {
                return "P";
            }
            if(str.CompareTo("亽")<0)
            {
                return "Q";
            }
            if(str.CompareTo("仨")<0)
            {
                return "R";
            }
            if(str.CompareTo("他")<0)
            {
                return "S";
            }
            if(str.CompareTo("哇")<0)
            {
                return "T";
            }
            if(str.CompareTo("夕")<0)
            {
                return "W";
            }
            if(str.CompareTo("丫")<0)
            {
                return "X";
            }
            if(str.CompareTo("帀")<0)
            {
                return "Y";
            }
            if(str.CompareTo("咗")<0)
            {
                return "Z";
            }
            return str;
        }
    }
}