Hope to change different page by dropdownlist inside child master page

Hi,   I have implemented two master pages, parent master page (with menu) and child master page (without menu).And I put the dropdownlist in child master page, Another two form-formA.aspx and formB.aspx about the master page is the child master page-- <% Page Language="VB" MasterPageFile="~/Child.master" ....%>
Now the value of dropdownlist(inside child master page) has A and B.I hope I change the value of dropdownlist to A,the page can be changed to formA.aspx,and change the value of dropdownlist to B,then the page can be changed to formB.aspx.
  Is it possible? Any idea I woud be so appreciated.