string utfinfo = "document.write(/"alert('你好么？？');/");";
string gb2312info = string.empty;

encoding utf8 = encoding.utf8;
encoding gb2312 = encoding.getencoding("gb2312");

// convert the string into a byte[].
byte[] unicodebytes = utf8.getbytes(utfinfo);
// perform the conversion from one encoding to the other.
byte[] asciibytes = encoding.convert(utf8, gb2312, unicodebytes);
           
// convert the new byte[] into a char[] and then into a string.
// this is a slightly different approach to converting to illustrate
// the use of getcharcount/getchars.
char[] asciichars = new char[gb2312.getcharcount(asciibytes, 0, asciibytes.length)];
gb2312.getchars(asciibytes, 0, asciibytes.length, asciichars, 0);
gb2312info = new string(asciichars);