中文转换为字母

string tempStr = "";         
foreach(char c in str)           
{               
if((int)c >= 33 && (int)c <=126)               
{//字母和符号原样保留                   
tempStr += c.ToString();    
}               
else               
{//累加拼音声母                   
tempStr += GetPYChar(c.ToString());             
}           
}          
return tempStr;       
}       
public string GetPYChar(string c)       
{          
byte[] array = new byte[2];           
array = System.Text.Encoding.Default.GetBytes(c);        
int i = (short)(array[0] - '\0') * 256 + ((short)(array[1] - '\0'));          
if ( i < 0xB0A1) return "*";           
if ( i < 0xB0C5) return "a";           
if ( i < 0xB2C1) return "b";           
if ( i < 0xB4EE) return "c";           
if ( i < 0xB6EA) return "d";           
if ( i < 0xB7A2) return "e";           
if ( i < 0xB8C1) return "f";           
if ( i < 0xB9FE) return "g";           
if ( i < 0xBBF7) return "h";           
if ( i < 0xBFA6) return "g";           
if ( i < 0xC0AC) return "k";           
if ( i < 0xC2E8) return "l";           
if ( i < 0xC4C3) return "m";           
if ( i < 0xC5B6) return "n";           
if ( i < 0xC5BE) return "o";           
if ( i < 0xC6DA) return "p";           
if ( i < 0xC8BB) return "q";           
if ( i < 0xC8F6) return "r";           
if ( i < 0xCBFA) return "s";           
if ( i < 0xCDDA) return "t";           
if ( i < 0xCEF4) return "w";           
if ( i < 0xD1B9) return "x";           
if ( i < 0xD4D1) return "y";           
if ( i < 0xD7FA) return "z";          
return "*"; 
}