Microsoft KB Archive/831150

= The &quot;Viewstate is invalid for this page&quot; error message does not provide sufficient information to troubleshoot the issue =

Article ID: 831150

Article Last Modified on 4/7/2006

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APPLIES TO


 * Microsoft .NET Framework 1.1
 * Microsoft Common Language Runtime (included with the .NET Framework 1.1)
 * Microsoft Visual Studio .NET 2003 Enterprise Architect
 * Microsoft Visual Studio .NET 2003 Enterprise Developer
 * Microsoft Visual Studio .NET 2003 Academic Edition

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For a Microsoft .NET Framework 1.0 version of this article, see 832183.



SUMMARY
Because View State is stored in a hidden field on a Web page, it is vulnerable to tampering when data is being transferred between the client and the server. To help make View State more secure, ASP.NET validates View State to verify that it came from the correct page.

If ASP.NET cannot validate View State, ASP.NET returns a message to the client browser that states that &quot;viewstate is invalid for this page and might be corrupted.&quot; However, the message does not describe why View State is not valid.

For more information about View State, see &quot;Description of View State&quot; in the &quot;More Information&quot; section of this article.



RESOLUTION
Although this article offers a hotfix, this hotfix does not fix View State errors. This hotfix provides additional information to help you troubleshoot View State errors.

Important This hotfix contains two types of packages: a Microsoft Windows Installer package, and an Optional Component Manager (OCM) package. If you use Microsoft Windows Server 2003, you must specify that you need the Windows Server 2003 (OCM) update because Windows Server 2003 File Protection monitors the Microsoft .NET Framework 1.1 files. If you use an operating system other than Windows Server 2003, you must use the Windows Installer package.

Hotfix information
A supported hotfix is now available from Microsoft, but it is only intended to correct the problem that is described in this article. Only apply it to systems that are experiencing this specific problem. This hotfix may receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next Microsoft .NET Framework 1.1 service pack that contains this hotfix.

To resolve this problem immediately, contact Microsoft Product Support Services to obtain the hotfix. For a complete list of Microsoft Product Support Services telephone numbers and information about support costs, visit the following Microsoft Web site:

http://support.microsoft.com/contactus/?ws=support

Note In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The usual support costs will apply to additional support questions and issues that do not qualify for the specific update in question.

Hotfix file information
The English version of this hotfix has the file attributes (or later) that are listed in the following table. The dates and times for these files are listed in coordinated universal time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time tool in Control Panel.   Date         Time   Version       Size       File name -  13-Nov-2003  03:16  1.1.4322.969    258,048  Aspnet_isapi.dll 13-Nov-2003 03:16  1.1.4322.969     20,480  Aspnet_regiis.exe 13-Nov-2003 03:16  1.1.4322.969     32,768  Aspnet_state.exe 13-Nov-2003 03:16  1.1.4322.969     32,768  Aspnet_wp.exe 16-May-2003 00:49                   33,522  Installpersistsqlstate.sql 16-May-2003 00:49                   34,150  Installsqlstate.sql 13-Nov-2003 03:06  1.1.4322.969     94,208  Perfcounter.dll 13-Nov-2003 17:38  1.1.4322.969  1,220,608  System.dll 13-Nov-2003 17:38  1.1.4322.969    241,664  System.messaging.dll 13-Nov-2003 17:38  1.1.4322.969    323,584  System.runtime.remoting.dll 13-Nov-2003 17:38  1.1.4322.969    131,072  System.runtime.serialization.formatters.soap.dll 13-Nov-2003 17:39  1.1.4322.969  1,257,472  System.web.dll 13-Nov-2003 17:38  1.1.4322.969    819,200  System.web.mobile.dll 13-Nov-2003 17:38  1.1.4322.969    569,344  System.web.services.dll 13-Nov-2003 17:39  1.1.4322.969  1,339,392  System.xml.dll 13-Nov-2003 03:11                   14,472  Webuivalidation.js

Hotfix details
This hotfix causes the View State error messages to contain more information. After you apply this hotfix, the View State error message title becomes &quot;Unable to Validate Data.&quot; The new error message format does not describe exactly what the problem is. However, this error message provides more information than the earlier error message format.

Note To obtain more information about the status of your View State, you can run the View State that appears in the error message through a third-party View State decoder.

This hotfix sets the InnerException property on the HttpException object so that you can use the Application_Error method to log the underlying exception. Make sure that you recursively log all InnerException property errors.

This hotfix adds the following information to the error message for View State errors:
 * IP address
 * Port number
 * User-Agent
 * Value of the View State
 * Http-Referer
 * Path of the requested page

If the error occurs while ASP.NET is verifying the View State message authentication code (MAC), this hotfix adds a message in the stack trace that prompts you to verify the  settings. The error message also states that the View State data can only be posted back to the same page.

If the error occurs during deserialization, this hotfix adds the LosFormater token, the _deserializationData token, and the position where the error occurred to the error message.

In most cases, if the View State data has been truncated, the View State feature will experience a FormatException error in the FromBase64String method, and you receive the following error message:

Invalid length for a Base-64 char array

However, if the View State data has been truncated and is still base64-encoded, the error will occur later in the code.

View State error message before you apply this hotfix
Server Error in '/ViewState' Application.

The viewstate is invalid for this page and might be corrupted.

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.Web.HttpException: The viewstate is invalid for this page and might be corrupted.

Source Error:

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.

Stack Trace:

[HttpException (0x80004005): The viewstate is invalid for this page and might be corrupted.]

System.Web.UI.Page.LoadPageStateFromPersistenceMedium +151

System.Web.UI.Page.LoadPageViewState +18

System.Web.UI.Page.ProcessRequestMain +423

View State error message after you apply this hotfix
Server Error in '/ViewState' Application.

Unable to validate data.

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.Web.HttpException: Unable to validate data.

Source Error:

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.

Stack Trace:

[HttpException (0x80004005): Unable to validate data.]

System.Web.Configuration.MachineKey.GetDecodedData(Byte[] buf, String strModifier) +866

System.Web.UI.LosFormatter.Deserialize(String input) +44

[HttpException (0x80004005): Authentication of viewstate failed. 1) If this is a cluster, edit  configuration so all servers use the same validationKey and validation algorithm. AutoGenerate cannot be used in a cluster. 2) Viewstate can only be posted back to the same page. 3) The viewstate for this page might be corrupted.]

System.Web.UI.LosFormatter.Deserialize(String input) +102

System.Web.UI.Page.LoadPageStateFromPersistenceMedium +101

[HttpException (0x80004005): The viewstate is invalid for this page and might be corrupted.

Client IP: 127.0.0.1

Port: 1095

User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; .NET CLR 1.0.3705)

ViewState: dDwzNDM3NTkwMzg7dDw7bDxpPDEPGk8MT47PjtsPHQ8QDA8cDxwPGw8RGF0YUt

Http-Referer: http://localhost/Connect2Access/WebForm1.aspx

Path: /connect2access/webform1.aspx.]

System.Web.UI.Page.LoadPageStateFromPersistenceMedium +435

System.Web.UI.Page.LoadPageViewState +16

System.Web.UI.Page.ProcessRequestMain +439

Note The ViewState value in this sample error message has been truncated to fit the context of this article.



STATUS
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the &quot;Applies to&quot; section.



MORE INFORMATION
For additional information about the terminology that is used to describe Microsoft product updates, click the following article number to view the article in the Microsoft Knowledge Base:

824684 Description of the standard terminology that is used to describe Microsoft software updates



Description of View State
ASP is stateless. Each time that an application makes a round trip from the server to the client, the data is not intrinsically saved. Each time that a Web page is posted to the server, the page is re-created. This behavior causes all information that is associated with the page, and with the controls on the page, to be lost for each round trip. For example, if a user types information in a text box, that information is lost in the round trip from the browser or from the client device to the server.

ASP.NET is also stateless. However, ASP.NET has a new feature, View State, that you can use to preserve data between round trips to and from the server. View State automatically preserves property values of the page, and the values of all controls on the page, between round trips. View State is maintained as a hidden field on the page.

You can use View State to store your own page-specific values across round trips when the page posts back to itself. For example, if your application is maintaining user-specific information, you can store this user-specific information in View State. User-specific information is information that is used on the page but that is not necessarily a part of any control.

back to the &quot;Summary&quot; section

Keywords: kbinfo kbtshoot kbbug kbfix kbwindbg kbqfe kbcode kbnetframe110sp1fix kbnetframe110presp1fix kbhotfixserver KB831150

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