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UsableDuringInitializationAttribute Class

Definition

Indicates whether this type is built top-down during XAML object graph creation.

public ref class UsableDuringInitializationAttribute sealed : Attribute
[System.AttributeUsage(System.AttributeTargets.Class, AllowMultiple=false, Inherited=true)]
public sealed class UsableDuringInitializationAttribute : Attribute
[<System.AttributeUsage(System.AttributeTargets.Class, AllowMultiple=false, Inherited=true)>]
type UsableDuringInitializationAttribute = class
    inherit Attribute
Public NotInheritable Class UsableDuringInitializationAttribute
Inherits Attribute
Inheritance
UsableDuringInitializationAttribute
Attributes

Remarks

Top-down is a metaphor that approximates XAML processor behavior when creating the object graph. When built top-down, a class is instantiated, attached to the parent, and then has its properties set. Top-down construction avoids invoking property-changed handlers multiple times. Such handling will ripple up the object graph and therefore eliminating the multiple handler calls provides a performance optimization for startup of the object graph.

In previous versions of the .NET Framework, this class existed in the WPF-specific assembly WindowsBase. In .NET Framework 4, UsableDuringInitializationAttribute is in the System.Xaml assembly. For more information, see Types Migrated from WPF to System.Xaml.

WPF Usage Notes

In WPF XAML for .NET Framework 3.0 and .NET Framework 3.5, top-down construction was built in to the XAML processing for certain classes. The UsableDuringInitializationAttribute attribute formalizes the reporting of the top-down behavior in .NET Framework 4.

Constructors

Name Description
UsableDuringInitializationAttribute(Boolean)

Initializes a new instance of the UsableDuringInitializationAttribute class.

Properties

Name Description
Usable

Gets a value that indicates whether the associated class is usable during initialization.

Applies to

See also