Consider the following scenario. In the Microsoft .NET Framework 2.0, you import a class from a Web Services Description Language (WSDL) file or from an XML Schema Document (XSD) file. You deserialize an object of the class from XML by using the XmlSerializer class. In this scenario, the deserialized object may contain null objects.

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This problem occurs when all the following conditions are true:

•	The WSDL file or XSD file contains at least one XSD choice statement.
•	The XSD choice statement contains at least one child element.
•	The child element sets the maxOccurs attribute to a value that is greater than 1 or to unbounded.

Additionally, the child element must meet one or more of the following conditions:

•	The name of the element does not match the name of the element type.
•	The form attribute of the element is set to unqualified.
•	If the element is a reference type, the nillable attribute is set to false. If the element is a value type, the nillable attribute is set to true.
•	The element data type has an ambiguous mapping to a .NET data type, so that the XmlElementAttribute.DataType property in the generated code must be set. For example, the element data type is set to xsd:date, xsd:time, xsd:ID, or xsd:token.

For example, the following example schema causes the problem that is mentioned in the "Symptoms" section:

<xsd:choice>
  ...
  <xsd:element name="ElementName" type="ElementType" maxOccurs="unbounded" form="unqualified" />
  ...
</xsd:choice>

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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 2.0 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: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 Microsoft .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.

File name	File version	File size	Date	Time
System.xml.dll	2.0.50727.103	2,035,712	19-Apr-2006	14:56

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

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For more information, click the following article number to view the article in the Microsoft Knowledge Base:

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