asp.net - Get child page data from master page selectedItems -

i have location dropdownlist in master page. have set control in child page takes properties master page. running query

select * table city '"+city.text+"' 

here city.text gets value master page selected cities. problem it's not showing records per city.text has values in it. shows random records.

my code

master page

<asp:dropdownlist id="locationselector" runat="server" autopostback="true">                         <asp:listitem selected>pune</asp:listitem>                         <asp:listitem>delhi</asp:listitem>                         <asp:listitem>chennai</asp:listitem>                         <asp:listitem>bangalore</asp:listitem>                         <asp:listitem>mumbai</asp:listitem>                     </asp:dropdownlist> 

child page vb code

dim location dropdownlist = page.master.findcontrol("locationselector")         city.text = location.selecteditem.tostring          if not ispostback             try                 query = "select * hospitals city '" + city.text + "'"                 dim cmd new mysqlcommand(query, con)                 cmd.commandtimeout = 120                 dim da new mysqldataadapter(cmd)                 dim table new datatable                 da.fill(table)                 viewstate("data") = table                 hospitals.datasource = table                 hospitals.databind()              catch ex exception                 response.write(ex)             end try         end if 

update

protected sub hospitals_prerender(byval sender object, byval e system.eventargs) handles me.prerender         dim location dropdownlist = page.master.findcontrol("locationselector")         city.text = location.selecteditem.tostring     end sub 

sometimes throws timeout error. of time gets results not per selected items. other solution this?

i suggest use prerender event within page. in prerender event try access master page control , value.