Updating a control outside the UpdatePanel
Place an UpdatePanel around the next button and create a trigger for each of the dropdowns so that it fires an async postback. Ex:
<Triggers> <asp:AsyncPostBackTrigger ControlID="dropDownList1" /> <asp:AsyncPostBackTrigger ControlID="dropDownList2" /> <asp:AsyncPostBackTrigger ControlID="dropDownList3" /></Triggers>
Could you not add a update panel around the "next page" and then add a trigger to the dropdownlist updatepanel for triggering the next page update panel?
Just throwing out ideas, without actually having tried it :)
you can upddate a control outside the update panel by placing it into update_panel2 and saying update_panel2.update().
Note the UpdateMode of the UpdatePanel must be set to conditionalfor this to work.