asp.net - error handing for uploading large size file -

how can send message user if file uploaded exceeds maximum limit on server side using asp.net. have wriiten following code in global.asax

sub application_error(byval sender object, byval e eventargs) dim ex new exception     ex = server.getlasterror()     if typeof ex httpunhandledexception andalso ex.innerexception isnot nothing         ex = ex.innerexception     end if     if (ex isnot nothing) , ex.message.contains("maximum request length exceeded")           server.clearerror()          server.transfer("/errors.aspx")     end if end sub 

it not display erros page instead internet explorer cannot display webpage

that's late in cycle. test in application_beginrequest this:

sub application_beginrequest(byval sender object, byval e eventargs)      dim runtime httpruntimesection = ctype(webconfigurationmanager.getsection("system.web/httpruntime"), httpruntimesection)     ' approx 100 kb(for page content) size has been deducted because maxrequestlength proprty      ' page size, not file upload size     dim maxrequestlength integer = (runtime.maxrequestlength - 100) * 1024     ' code used check request length of page , if request length      ' greater maxrequestlength return same page query string value action=exception     dim mycontext httpcontext = ctype(sender, httpapplication).context      if mycontext.request.contentlength > maxrequestlength          ' need consume file otherwise browser detect upload did not complete          ' , assume connection broken , display "page not found" error         dim pro iserviceprovider = ctype(mycontext, iserviceprovider)         dim workerrequest httpworkerrequest = directcast(pro.getservice(gettype(httpworkerrequest)), httpworkerrequest)         if workerrequest.hasentitybody             dim requestlength integer = workerrequest.gettotalentitybodylength             dim initialbytes integer = 0             if workerrequest.getpreloadedentitybody isnot nothing                 initialbytes = workerrequest.getpreloadedentitybody.length             end if             if not workerrequest.isentireentitybodyispreloaded                 dim buffer byte() = new byte(511999) {}                 dim receivedbytes integer = initialbytes                 while (requestlength - receivedbytes) >= initialbytes                     initialbytes = workerrequest.readentitybody(buffer, buffer.length)                     receivedbytes += initialbytes                 end while                 initialbytes = workerrequest.readentitybody(buffer, requestlength - receivedbytes)             end if              response.redirect("~/utility/errormaxlength.htm")         end if     end if  end sub 

source http://weblogs.asp.net/hosamkamel/resolving-maximum-request-length-exceeded-exception