请问，C#中如何对“quoted-printable”编码方式的字符串进行解码？

Question

/*Quoted-Printable 解码*/                                     
private String deCodeQP(String strSrc)                        
{                                                             
                                                              
char ch, ch1, ch2;                                    
char[] hz;                                            
String strRet="";                                     
hz=strSrc.ToCharArray();                              
for (int i=0;i<strSrc.Length;i++)                     
{                                                     
ch = hz[i];                                   
if (ch == '=')                                
{                                             
i++;                                  
ch1 = hz[i];                          
if (ch1 == '\n') continue;            
i++;                                  
ch2 = hz[i];                          
int chint1,chint2;                    
if (ch1>'9')                          
{                                     
chint1=(ch1-'A'+10)*16;       
}                                     
else                                  
{                                     
chint1=(ch1-'0')*16;          
}                                     
if (ch2>'9')                          
{                                     
chint2=ch1-'A'+10;            
}                                     
else                                  
{                                     
chint2=ch1-'0';               
}                                     
ch = Convert.ToChar(chint1 + chint2); 
}                                             
strRet += ch.ToString();                      
}                                                     
return strRet;                                        
}