C#,.Net自动生成大写字母编码

public static string GetChineseSpell(string strText)
{
int len = strText.Length;
string myStr = "";
for (int i = 0; i < len; i++)
{
myStr += getSpell(strText.Substring(i,1));
}
return myStr;
}

public static string getSpell(string cnChar)
{
byte[] arrCN = Encoding.Default.GetBytes(cnChar);
if (arrCN.Length > 1)
{
int area = (short)arrCN[0];
int pos = (short)arrCN[1];
int code = (area << 8) + pos;
int[] areacode = { 45217,45253,45761,46318,46826,47010,47297,47614,48119,49062,49324,49896,50371,50614,50622,50906,51387,51446,52218,52698,52980,53689,54481 };
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 cnChar;
}