如何获取到%形式的GB2312的编码

这个编码是指形如这样子的编码:%B8%C4%B8%EF

private string GetGB2312(string text)
{
byte[] bs = Encoding.GetEncoding("UTF-8").GetBytes(text);
bs = Encoding.Convert(Encoding.GetEncoding("UTF-8"), Encoding.GetEncoding("GB2312"), bs);
string gb2312 = "";
foreach (byte b in bs)
{
gb2312 += "%"+Convert.ToString(b, 16).ToUpper();
}
return gb2312;
}