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NullExtension Class

Implements a XAML markup extension in order to return a null object, which you can use to explicitly set values to a null reference (Nothing in Visual Basic).

Namespace: System.Windows.Markup
Assembly: PresentationFramework (in presentationframework.dll)
XML Namespace:  http://schemas.microsoft.com/winfx/2006/xaml

[MarkupExtensionReturnTypeAttribute(typeof(Object))] 
public class NullExtension : MarkupExtension
/** @attribute MarkupExtensionReturnTypeAttribute(System.Object) */ 
public class NullExtension extends MarkupExtension
MarkupExtensionReturnTypeAttribute(System.Object) 
public class NullExtension extends MarkupExtension
 For XAML information, see x:Null Markup Extension. 

This class is a markup extension implementation. Markup extension classes exist mainly to provide infrastructure support for how WPF XAML readers interpret a particular extension. The members that markup extension implementation classes expose are not typically intended to be called from your code. This markup extension class supports the x:Null Markup Extension usage for XAML.

When you set a dependency property value to a null reference (Nothing in Visual Basic), you are not necessarily setting the property to its default value. The default value of a dependency property depends on its dependency property registration. For more information, see ClearValue.

System.Object
   System.Windows.Markup.MarkupExtension
    System.Windows.Markup.NullExtension
Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

Windows 98, Windows Server 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 3.0
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