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FIX: You receive a System.ArgumentException exception error message when you use the Sgen.exe tool and the XmlSerializer JIT compiler to generate an XmlSerializer assembly for a Web service proxy in the .NET Framework 2.0

SYMPTOMS
You have a Microsoft .NET Framework 2.0-based project that uses Web service proxies. When you use the Sgen.exe tool and the XmlSerializer just-in-time (JIT) compiler to generate an XmlSerializer assembly for one of the Web service proxies, you receive the following exception error message:
System.ArgumentException: Item has already been added. Key in dictionary: **** Key being added: ****
This problem occurs when one of the following conditions is true:
  • The project has a class that derives from a Web service proxy class.
  • The project has two Web service proxies that use the same custom data types in the same assembly.
CAUSE
This problem occurs because of a code issue in the .NET Framework 2.0.
RESOLUTION

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: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 Service Pack 1 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 global 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, x86-based versions
File nameFile versionFile sizeDateTimePlatform
System.xml.dll2.0.50727.18322,052,09614-May-200802:43x86
The .NET Framework 2.0, Itanium architecture versions
File nameFile versionFile sizeDateTimePlatform
System.xml.dll2.0.50727.18322,052,09614-May-200802:43x86
System.xml.dll2.0.50727.18322,052,09614-May-200801:38x86
The .NET Framework 2.0, x64-based versions
File nameFile versionFile sizeDateTimePlatform
System.xml.dll2.0.50727.18322,052,09614-May-200802:43x86
System.xml.dll2.0.50727.18322,052,09614-May-200801:38x86
WORKAROUND
To work around this problem, split the Web service references into separate .dll files. When you do this, there is only one Web reference per assembly.
STATUS
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
MORE INFORMATION
For more information about the Sgen.exe tool, visit the following Microsoft Developer Network (MSDN) Web site:For more information about software update terminology, 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
Serialization key in dictionary System.ArgumentException
Properties

Article ID: 950230 - Last Review: 10/08/2011 08:40:00 - Revision: 2.0

Microsoft .NET Framework 2.0

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