Hi,
After installing .NET 3.5 SP1, I realized some problems on my old project which has written on framework 2.0.
My observations/symptoms on the project-login form:
- IsPostBack was always false
- İmagebutton click event not firing
- I could not login the system
After 2 days searching ,luckily I stumbled upon following page. Thanks god :) http://blogs.msdn.com/tess/archive/2009/04/14/validation-of-viewstate-mac-failed-after-installing-net-3-5-sp1.aspx?CommentPosted=true#commentmessage
Cause:
There was a form tag in the Login.aspx. Pay attention to action="Default.aspx" (this was the problem)
<form id="form1" method="post" action="Default.aspx" runat="server">
This problem may occur if your page(in this case Login.aspx) and form action property(Default.aspx) are different.
Reason :
This occurs after installing SP1 for .NET 3.5 is because prior to this service pack, the action property was ignored. Now that it is no longer ignored.It will work properly. I mean, this is not a bug, it’s a feature...
Solution:
Remove the form-action property or change it to post correct page(in this case Login.aspx).
References :
http://blogs.iis.net/webtopics/archive/2009/05/13/httpexception-due-to-invalid-viewstate-after-installing-net-framework-3-5-sp1.aspx
http://blogs.msdn.com/tess/archive/2009/04/14/validation-of-viewstate-mac-failed-after-installing-net-3-5-sp1.aspx?CommentPosted=true#commentmessage
See you soon....
Tags: net framework 3.5 sp1