Microsoft KB Archive/940900

= FIX: You receive the NullReferenceException exception when you call the String.IsNullOrEmpty function in an application that is built on the .NET Framework 2.0 =

Article ID: 940900

Article Last Modified on 9/3/2007

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APPLIES TO


 * Microsoft .NET Framework 2.0

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SYMPTOMS
When you call the String.IsNullOrEmpty function in an application that is built on the Microsoft .NET Framework 2.0, you receive the NullReferenceException exception. This problem occurs if the following conditions are true:
 * You call the String.IsNullOrEmpty function by using a NULL parameter, and you use the function in a loop.
 * You build the application in release mode with the default build settings.



CAUSE
This problem occurs because of a problem in compiler optimizations.



Hotfix information
A supported hotfix is now available from Microsoft. However, it is intended to correct only the problem that is described in this article. Apply it only 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 .NET Framework 2.0 service pack that contains this hotfix.

To resolve this problem immediately, 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:

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.

Prerequisites
You must have the .NET 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.

The .NET Framework 2.0, Itanium architecture versions


WORKAROUND
To work around this problem, use one of the following methods:  In Visual studio 2005, right-click the project in Solution Explorer, click Properties on the Build tab, and then click to clear the Optimize code check box.  Replace all calls to the IsNullOrEmpty function inside a loop with the following: SomeString == NULL || string.IsNullOrEmpty(SomeString) 



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 more information, 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

Keywords: kbfix kbqfe kbpubtypekc kbexpertiseadvanced kbhotfixserver KB940900

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