Errors: Failed to load viewstate. & Validation of viewstate MAC failed.

  • Thread starter Thread starter sck10
  • Start date Start date
S

sck10

Hello,

I have applications that produce the following error when they have been
open to long without activity. Is there any way to force a re-load of the
page or go to another page if the page has expired instead of getting the
error?

Thanks,


Failed to load viewstate. The control tree into which viewstate is being
loaded must match the control tree that was used to save viewstate during
the previous request. For example, when adding controls dynamically, the
controls added during a post-back must match the type and position of the
controls added during the initial request.


Server Error in '/' Application.
Validation of viewstate MAC failed. If this application is hosted by a Web
Farm or cluster, ensure that <machineKey> configuration specifies the same
validationKey and validation algorithm. AutoGenerate cannot be used in a
cluster.
 
A few preliminary questions: are you hosted on a web farm; if so, do
you have enableViewStateMac set to false in your Web.Config, for
example:

<pages enableViewStateMac="false"/>
 
Hello Steve,

From your description, the problem occurs when the page has been idle for
long time. Does it occur when the page is display in short time and be
fresh? For long time idle page, I think the exception is likely due to the
viewstate MAC has been expired and the server runtime can not validate it.
ASP.NET will perform a simple digest on the viewstate and check it later
when page postback, however, this digest is not valid forever, after long
period, it could refresh it. I've also seen some one encountering such
problem when using page cached in google page cache.

For your another question:
================
Is there any way to force a re-load of the
page or go to another page if the page has expired instead of getting the
error?
================

Do you think use client-side script to set a timer and postback/reload the
page after a certain periold workable for you? e.g.

#the following page use script to reload the page after 20 secs
==================
....................
<script type="text/javascript">
function client_onload()
{
window.setTimeout("refresh_page()", 20000);
}

function refresh_page()
{
window.location.href = window.location.href;
}
</script>
</head>
<body onload="client_onload();">
<form id="form1" runat="server" >
<div>
..............
===============

Hope this helps.

Sincerely,

Steven Cheng

Microsoft MSDN Online Support Lead



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