.NET Framework Class Library
UsableDuringInitializationAttribute Class

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

Inheritance Hierarchy

Namespace:   System.Windows.Markup
Assembly:  System.Xaml (in System.Xaml.dll)
<[%$TOPIC/cc452107_en-us_VS_110_2_0_0_0_0%]([%$TOPIC/cc452107_en-us_VS_110_2_0_0_0_1%].Class, AllowMultiple := False, Inherited := True)> _
Public NotInheritable Class UsableDuringInitializationAttribute _
	Inherits [%$TOPIC/cc452107_en-us_VS_110_2_0_0_0_2%]
[[%$TOPIC/cc452107_en-us_VS_110_2_0_1_0_0%]([%$TOPIC/cc452107_en-us_VS_110_2_0_1_0_1%].Class, AllowMultiple = false, Inherited = true)]
public sealed class UsableDuringInitializationAttribute : [%$TOPIC/cc452107_en-us_VS_110_2_0_1_0_2%]
[[%$TOPIC/cc452107_en-us_VS_110_2_0_2_0_0%]([%$TOPIC/cc452107_en-us_VS_110_2_0_2_0_1%]::Class, AllowMultiple = false, Inherited = true)]
public ref class UsableDuringInitializationAttribute sealed : public [%$TOPIC/cc452107_en-us_VS_110_2_0_2_0_2%]
[<[%$TOPIC/cc452107_en-us_VS_110_2_0_3_0_1%]([%$TOPIC/cc452107_en-us_VS_110_2_0_3_0_2%].Class, AllowMultiple = false, Inherited = true)>]
type UsableDuringInitializationAttribute =  
        inherit [%$TOPIC/cc452107_en-us_VS_110_2_0_3_0_3%] 
public final class UsableDuringInitializationAttribute extends [%$TOPIC/cc452107_en-us_VS_110_2_0_4_0_0%]

The UsableDuringInitializationAttribute type exposes the following members.

Public method UsableDuringInitializationAttributeInitializes a new instance of the UsableDuringInitializationAttribute class.
Public property TypeIdWhen implemented in a derived class, gets a unique identifier for this Attribute. (Inherited from Attribute.)
Public property UsableGets a value that indicates whether the associated class is usable during initialization.
Public method EqualsInfrastructure. Returns a value that indicates whether this instance is equal to a specified object. (Inherited from Attribute.)
Public method GetHashCodeReturns the hash code for this instance. (Inherited from Attribute.)
Public method GetTypeGets the Type of the current instance. (Inherited from Object.)
Public method IsDefaultAttributeWhen overridden in a derived class, indicates whether the value of this instance is the default value for the derived class. (Inherited from Attribute.)
Public method MatchWhen overridden in a derived class, returns a value that indicates whether this instance equals a specified object. (Inherited from Attribute.)
Public method ToStringReturns a string that represents the current object. (Inherited from Object.)
Explicit Interface Implementations
Explicit interface implemetation Private method _AttributeGetIDsOfNamesMaps a set of names to a corresponding set of dispatch identifiers. (Inherited from Attribute.)
Explicit interface implemetation Private method _AttributeGetTypeInfoRetrieves the type information for an object, which can be used to get the type information for an interface. (Inherited from Attribute.)
Explicit interface implemetation Private method _AttributeGetTypeInfoCountRetrieves the number of type information interfaces that an object provides (either 0 or 1). (Inherited from Attribute.)
Explicit interface implemetation Private method _AttributeInvokeProvides access to properties and methods exposed by an object. (Inherited from Attribute.)

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.

Version Information

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5 SP1, 3.0 SP2

.NET Framework Client Profile

Supported in: 4, 3.5 SP1
Thread Safety
Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.