asp.net - VB.NET redirection loop error -

i have following code on multilingual website: (masterpage.master.vb)

dim pageurl string = httpcontext.current.request.url.absolutepath  protected sub page_load(sender object, e system.eventargs) handles me.load      dim strlanguage string = session("language")      if not ispostback          response.redirect(string.format("{0}?language={1}", pageurl, strlanguage))      end if      response.write(string.format("{0}?idioma={1}", pageurl, strlanguage)) end sub 

it display querystrings: '?language=es' or '?language=en' @ end of current url, when run web, browser displays message: page has redirect loop (err_too_many_redirects).

why happening? how can fix this?

thanks in advance

edit: tried with:

if ispostback 

but when that, querystring doesn't appear @ end of url.

edit 2 (solved): works @ last! thank zed, final code follows:

     dim pageurl string = httpcontext.current.request.url.absolutepath  protected sub page_load(sender object, e system.eventargs) handles me.load      dim strlanguage string = session("language")      if not ispostback          if request.querystring("language") nothing             response.redirect(string.format("{0}?language={1}", pageurl, strlanguage))         end if     else         if not request.querystring("language") nothing             response.redirect(string.format("{0}?language={1}", pageurl, strlanguage))         end if     end if      response.write(string.format("{0}?language={1}", pageurl, strlanguage)) end sub 

you redirecting @ first page load. see:

    if not ispostback          response.redirect(string.format("{0}?language={1}", pageurl, strlanguage))      end if 

when first visit page uses master page, redirected again, , again, , again (by way, redirection not postback)

depending on need achieve, may have make kind of check before doing redirect, or occur. ask, instance, if language not present in querystring, , redirection:

if not ispostback     if request.querystring("language") nothing         response.redirect(string.format("{0}?language={1}", pageurl, strlanguage))     end if end if