Why do I get Cannot redirect after HTTP headers have been sent when I call Response Redirect

Question

When I call Response Redirect someUrl  I get the following HttpException      Cannot redirect after HTTP headers have been sent    Why do I get this  And how can I fix this issue

User · Answer

Error Cannot redirect after HTTP headers have been sent   System Web HttpException  0x80004005   Cannot redirect after HTTP headers have been sent   Suggestion If we use asp net mvc and working on same controller and redirect to different Action then you do not need to write    Response Redirect  ActionName   ControllerName    its better to use only  return RedirectToAction  ActionName    or  return View  ViewName

User · Answer

My Issue got resolved by adding the Exception Handler to handle  Cannot redirect after HTTP headers have been sent   this Error as shown below code  catch  System Threading ThreadAbortException                           To Handle HTTP Exception  Cannot redirect after HTTP headers have been sent                     catch  Exception e             Here you can put your context response redirect  page aspx

User · Answer

According to the MSDN documentation for Response Redirect string url   it will throw an HttpException when  a redirection is attempted after the HTTP headers have been sent    Since Response Redirect string url  uses the Http  Location  response header  http   en wikipedia org wiki HTTP headers Responses   calling it will cause the headers to be sent to the client   This means that if you call it a second time  or if you call it after you ve caused the headers to be sent in some other way  you ll get the HttpException   One way to guard against calling Response Redirect   multiple times is to check the Response IsRequestBeingRedirected property  bool  before calling it      Causes headers to be sent to the client  Http  Location  response header  Response Redirect  http   www stackoverflow com    if   Response IsRequestBeingRedirected         Will not be called     Response Redirect  http   www google com

User · Answer

There is one simple answer for this  You have been output something else  like text  or anything related to output from your page before you send your header  This affect why you get that error    Just check your code for posible output or you can put the header on top of your method so it will be send first

User · Answer

The redirect function probably works by using the  refresh  http header  and maybe using a 30X code as well   Once the headers have been sent to the client  there is not way for the server to append that redirect command  its too late

User · Answer

Using  return RedirectPermanent myUrl  worked for me

User · Answer

Just check if you have set the buffering option to false  by default its true   For response redirect to work    Buffering should be true  you should not have sent more data using response write which exceeds the default buffer size  in which case it will flush itself causing the headers to be sent  therefore disallowing you to redirect

User · Answer

I solved the problem using  Response RedirectToRoute  CultureEnabled   RouteData Values   instead of Response Redirect

User · Answer

Be sure that you don t use Responses  methods like Response Flush    before your redirecting part

User · Answer

If you are trying to redirect after the headers have been sent  if  for instance  you are doing an error redirect from a partially-generated page   you can send some client Javascript  location replace or location href  etc   to redirect to whatever URL you want   Of course  that depends on what HTML has already been sent down

User · Answer

A Redirect can only happen if the first line in an HTTP message is  HTTP 1 x 3xx Redirect Reason    If you already called Response Write   or set some headers  it ll be too late for a redirect  You can try calling Response Headers Clear   before the Redirect to see if that helps

User · Answer

Once you send any content at all to the client  the HTTP headers have already been sent   A Response Redirect   call works by sending special information in the headers that make the browser ask for a different URL     Since the headers were already sent  asp net can t do what you want  modify the headers   You can get around this by a  either doing the Redirect before you do anything else  or b  try using Response Buffer   true before you do anything else  to make sure that no output is sent to the client until the whole page is done executing

User · Answer

There are 2 ways to fix this    Just add a return statement after your Response Redirect someUrl     if the method signature is not  void   you will have to return that  type   of course   as so   Response Redirect  Login aspx     return    Note the return allows the server to perform the redirect   without it  the server wants to continue executing the rest of your code      Make your Response Redirect someUrl  the LAST executed statement in the method that is throwing the exception  Replace your Response Redirect someUrl  with a string VARIABLE named  someUrl   and set it to the redirect location    as follows            some code  string someUrl   String Empty        some logic  if  x y           comment  original location of Response Redirect  Login aspx         someUrl    Login aspx             more code     MOVE your Response Redirect to HERE  the end of the method    Response Redirect someUrl   return

User · Answer

If you get Cannot redirect after HTTP headers have been sent then try this below code     HttpContext Current Server ClearError       Response Headers Clear    HttpContext Current Response Redirect   Home Login  false

User · Answer

You can also use below mentioned code   Response Write   lt script type  text javascript  gt     Response Write  window location        redirect url      lt  script gt    Response Flush

[asp.net] Why do I get "Cannot redirect after HTTP headers have been sent" when I call Response.Redirect()?

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