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

原文：http://blog.csdn.net/hawk1404/article/details/18279683