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FrameworkElement.ParentLayoutInvalidated Method

Supports incremental layout implementations in specialized subclasses of FrameworkElement. ParentLayoutInvalidated is invoked when a child element has invalidated a property that is marked in metadata as affecting the parent's measure or arrange passes during layout.

Namespace: System.Windows
Assembly: PresentationFramework (in presentationframework.dll)

'Declaration
Protected Friend Overridable Sub ParentLayoutInvalidated ( _
	child As UIElement _
)
'Usage
Dim child As UIElement

Me.ParentLayoutInvalidated(child)
protected void ParentLayoutInvalidated (
	UIElement child
)
protected internal function ParentLayoutInvalidated (
	child : UIElement
)
You cannot use methods in XAML.

Parameters

child

The child element reporting the change.

If this element has a child element on which some property was invalidated and the property was marked as AffectsParentMeasure or AffectsParentArrange in property metadata during registration, this method is invoked. The method invocation notifies the parent element which particular child element must be re-measured if this element supports partial (incremental) update of layout.

By default, FrameworkElement does not support incremental layout, and in the FrameworkElement class this method has no default implementation. The scenario where overriding this method would be necessary is not common, because it requires you to modify the default layout system behavior.

An example implementation scenario might be if a class had type limitations for possible child elements that are significantly more restrictive than the WPF framework-level layout system. Because of the nature of these custom elements, property changes could be deliberately deferred when you implement some custom layout behavior. For instance, measure/arrange method overrides, which try to optimize the child element render pass, could be deferred for certain types of changes that would ordinarily result in another layout pass.

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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