大家哪位高手帮小弟我改一下下面这代码,改得效率高点

大家谁帮我改一下下面这代码,改得效率高点
其它s固定为2个字符的字符串(如00,   01,   09,   A0,   A9,   BB,   D9,   EF等),
用于返回其对应的HEX的十进制
怎么做效率高一点?

Public   Function   stohex(ByVal   s   As   String)   As   Integer
        Dim   stemp   As   String
        ss   =   s
        If   Len(ss)   =   2   Then
          If   Mid(ss,   1,   1)   =   "0 "   Then
              ss   =   Mid(ss,   2,   1)
          End   If
        End   If
        For   i   =   0   To   10000
              stemp   =   UCase(hex(i))
              If   stemp   =   UCase(ss)   Then
                    stohex   =   i
                    Exit   Function
              End   If
        Next   i
        stohex   =   -1
End   Function

------解决方案--------------------
s = "FF "
i = Val( "&H " + s)
MsgBox Str(i)

------解决方案--------------------
Dim ss As String * 2, i As Integer
ss = "af "
i = "&h " & ss
Print i