Select the product you need help with
- Internet Explorer
- Windows Phone
- More products
FIX: ASP.NET returns a "NullReferenceException" error message when you use SQL Server Session state and you turn on the OutPutCaching feature
Article ID: 831382 - View products that this article applies to.
When you use the Microsoft SQL Server Session state, and you turn on the OutPutCaching feature for a Web page, if you set the Location attribute to Client (<%@ OutputCache Location="Client" Duration="900" VaryByParam="WaitMessage" %>), a user may receive the following error message when the user accesses the Web page more than one time:
When this problem occurs, a stack trace that is similar to the following appears in the client window:
NullReferenceException: "Object reference not set to an instance of an object"
The first time that a user accesses the Web page, Microsoft ASP.NET caches a copy of the Web page by using the user's unique session ID. The ASP.NET worker process uses this cached copy of the Web page for all later page rendering. After 900 seconds, the cache expires. Then the cached copy of the Web page is deleted from memory. However, the user's session ID is still active.
When the user tries to access the Web page again, the user receives the error message that appears in the "Symptoms" section because the cached copy of the Web page has been deleted.
Software update informationA supported software update 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 software update may receive additional testing. Therefore, if you are not severely affected by this problem, Microsoft recommends that you wait for the next Microsoft .NET Framework 1.0 service pack that contains this software update.
To resolve this problem immediately, contact Microsoft Product Support Services to obtain the software update. For a complete list of Microsoft Product Support Services phone numbers and information about support costs, visit the following Microsoft Web site:
http://support.microsoft.com/default.aspx?scid=fh;[LN];CNTACTMSNote 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.
PrerequisitesYou must have the .NET Framework 1.0 Service Pack 2 installed to install this hotfix.
Restart requirementYou may have to restart your computer after you apply this software update if any services or applications that use files that appear in the "File information" section of this article are running when you apply this software update.
Restart requirementThis software update does not replace any other software updates.
File informationThe English version of this software update 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 tool in Control Panel.
Date Time Version Size File name --------------------------------------------------------------------------------------------- 09-Nov-2003 01:45 1.0.3705.468 200,704 Aspnet_isapi.dll 09-Nov-2003 01:38 4,169 Aspnet_perf.h 09-Nov-2003 01:45 513,302 Aspnet_perf.ini 09-Nov-2003 01:45 510,714 Aspnet_perf2.ini 09-Nov-2003 01:45 1.0.3705.468 24,576 Aspnet_regiis.exe 09-Nov-2003 01:45 1.0.3705.468 28,672 Aspnet_wp.exe 09-Nov-2003 00:59 1.0.3705.468 69,632 Corperfmonext.dll 17-Jun-2003 21:43 16,597 Installpersistsqlstate.sql 17-Jun-2003 21:43 17,331 Installsqlstate.sql 09-Sep-2003 00:28 17,807 Installsqlstatetemplate.sql 09-Nov-2003 00:58 1.0.3705.468 303,104 Mscorjit.dll 10-Nov-2003 18:11 1.0.3705.468 1,953,792 Mscorlib.dll 09-Nov-2003 00:51 10,284 Mscorlib.ldo 09-Nov-2003 00:58 1.0.3705.468 2,273,280 Mscorsvr.dll 09-Nov-2003 00:59 1.0.3705.468 2,269,184 Mscorwks.dll 09-Nov-2003 01:42 1.0.3705.468 20,480 Perfcounter.dll 23-Aug-2002 02:23 15 Smartnav.htm 30-Jul-2003 00:04 8,728 Smartnav.js 10-Nov-2003 17:53 1.0.3705.468 1,179,648 System.data.dll 10-Nov-2003 18:10 1.0.3705.468 1,695,744 System.design.dll 10-Nov-2003 17:53 1.0.3705.468 1,175,552 System.dll 10-Nov-2003 17:51 1.0.3705.468 241,664 System.messaging.dll 10-Nov-2003 17:51 1.0.3705.468 311,296 System.runtime.remoting.dll 10-Nov-2003 17:49 1.0.3705.468 131,072 System.runtime.serialization.formatters.soap.dll 10-Nov-2003 17:55 1.0.3705.468 1,196,032 System.web.dll 10-Nov-2003 17:51 1.0.3705.468 507,904 System.web.services.dll 10-Nov-2003 18:12 1.0.3705.468 1,994,752 System.windows.forms.dll 09-Nov-2003 01:51 16,776 System.windows.forms.ldo 09-Nov-2003 01:47 1.0.3705.468 57,344 System.windows.forms.tlb 10-Nov-2003 18:08 1.0.3705.468 1,302,528 System.xml.dll 10-Nov-2003 17:47 1.0.3705.468 32,768 Tlbimp.exe 17-Jun-2003 21:43 1,419 Uninstallpersistsqlstate.sql 09-Sep-2003 00:28 2,119 Uninstallsqlstatetemplate.sql 10-Nov-2003 17:48 1.0.3705.468 65,536 Wsdl.exe
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
By default, the OutputCache directive is set to Server. To reproduce the problem, set the OutputCache directive to Client, as in the following example:
For more 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:
(http://support.microsoft.com/kb/824684/ )Description of the standard terminology that is used to describe Microsoft software updates
For more information, click the following article numbers to view the articles in the Microsoft Knowledge Base:
(http://support.microsoft.com/kb/317604/ )How to configure SQL Server to store ASP.NET Session State
(http://support.microsoft.com/kb/315896/ )How to improve performance by caching pages in ASP.NET
Article ID: 831382 - Last Review: October 25, 2005 - Revision: 1.5