vb.net把汉字转换为GB2312编码,例如“广东”变成%B9%E3%B6%AB

gb2312是gbk编码的子集，使用gbk编码函数即可
'gbk编码(结果以百分号%进行分隔)
public function gbkencode(byval sinput as string) as string
dim ret_gbkencode as string = ""
dim i as integer
dim startindex as integer = 0
dim endindex as integer
dim x() as byte = system.text.encoding.default.getbytes(sinput) '字符以及字符串在vb2008中都是以unicode编码存储的

endindex = x.length - 1
for i = startindex to endindex
ret_gbkencode &= "%" & hex(x(i))
next
return ret_gbkencode
end function

'gbk解码
public function gbkdecode(byval sinput as string) as string
sinput = sinput.replace("%", "")

dim ret_gbkdecode as string = ""
dim slen as integer = sinput.length
dim n as integer = slen \ 2
dim sbytes(0 to n - 1) as byte
'转化为字节码
for i as integer = 1 to n
sbytes(i - 1) = cbyte("&h" & sinput.substring(2 * i - 2, 2))
next
'将字节码转化为字符串
ret_gbkdecode = system.text.encoding.default.getstring(sbytes)
return ret_gbkdecode
end function