FIX: An InvalidViewState exception is not thrown as expected when you use the Triple DES encryption type to validate the System.Web.UI.Control.ViewState property in the .NET Framework 2.0

When you use the Triple DES (3DES) encryption type to validate the System.Web.UI.Control.ViewState property in the Microsoft .NET Framework 2.0, and you set the System.Web.UI.Page.ViewStateUserKey property to an incorrect value, an InvalidViewState exception is not thrown as expected.

Hotfix information

A supported hotfix is now available from Microsoft. However, it is intended to correct only the problem that this article describes. Apply it only to systems that are experiencing this specific problem.

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

Prerequisites

You must have the Framework 2.0 installed to apply this hotfix.

Restart requirement

You do not have to restart the computer after you apply this hotfix.

Hotfix replacement information

This hotfix does not replace any other hotfixes.

File information

The English version of this hotfix has the file attributes (or later file attributes) 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 item in Control Panel.

Microsoft .NET Framework 2.0, x86-based versions

Microsoft .NET Framework 2.0, x64-based versions

Microsoft .NET Framework 2.0, Itanium-based versions

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.

After you apply this hotfix, you may still receive the exception that is mentioned in the “Symptoms” section. This problem occurs if the following conditions are true:

• You have two ASP.NET 2.0 Web pages. Assume that the names of the two ASP.NET 2.0 Web pages are Page1.aspx and Page2.aspx.
• In Page1.aspx, you set the value of the ViewStateEncryptionMode attribute to Always.
• In Page1.aspx, you use JavaScript to set the form.action property to reference Page2.aspx and then to call the form.submit function.
• In Page2.aspx, you set the value of the ViewStateEncryptionMode attribute to Never.
• When you run the pages, you post the encrypted ViewState property to Page2.aspx, and Page2.aspx does not expect the encrypted ViewState property.

To resolve this problem, use one of the following methods.

Method 1

Make sure that the ViewStateEncryptionMode attribute is synchronous in both of the two ASP.NET 2.0 Web pages.

Method 2

Use JavaScript to add logic to clear the __ViewState form field when you change the form.action property. For example, use the following code to add logic.

Method 3

Use an ASP.NET button control, and then perform the postback operation by setting the PostBackUrl property of the button control. This operation not only sets the form.action property in JavaScript but also sets a __PREVIOUSPAGE form field. Therefore, the ViewState property is repopulated during the postback operation. This avoids the problem.

For more information about software update terminology, click the following article number to view the article in the Microsoft Knowledge Base:The third-party products that this article discusses are manufactured by companies that are independent of Microsoft. Microsoft makes no warranty, implied or otherwise, about the performance or reliability of these products.