UsableDuringInitializationAttribute 类

定义

指示在 XAML 对象图创建期间是否自上而下生成此类型。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
type UsableDuringInitializationAttribute = class
    inherit Attribute
Public NotInheritable Class UsableDuringInitializationAttribute
Inherits Attribute
继承
UsableDuringInitializationAttribute
属性

注解

从上到下是在创建对象图时, 与 XAML 处理器行为接近的比喻。Top-down is a metaphor that approximates XAML processor behavior when creating the object graph. 当自上而下生成时, 会实例化类, 并将其附加到父, 然后设置其属性。When built top-down, a class is instantiated, attached to the parent, and then has its properties set. 自上而下的构造避免多次调用属性更改的处理程序。Top-down construction avoids invoking property-changed handlers multiple times. 此类处理会使对象图出现在一起, 从而消除了多个处理程序调用为对象图的启动提供了性能优化。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.

在 .NET Framework 的以前版本中, 此类存在于 WPF 特定的程序集 WindowsBase 中。In previous versions of the .NET Framework, this class existed in the WPF-specific assembly WindowsBase. .NET Framework 4.NET Framework 4UsableDuringInitializationAttribute , 为 system.exception 程序集。In .NET Framework 4.NET Framework 4, UsableDuringInitializationAttribute is in the System.Xaml assembly. 有关详细信息,请参阅 Types Migrated from WPF to System.XamlFor more information, see Types Migrated from WPF to System.Xaml.

WPF 用法说明WPF Usage Notes

.NET Framework 3.0.NET Framework 3.0.NET Framework 3.5.NET Framework 3.5的 WPF XAML 中, 自顶向下构造内置于特定类的 XAML 处理中。In WPF XAML for .NET Framework 3.0.NET Framework 3.0 and .NET Framework 3.5.NET Framework 3.5, top-down construction was built in to the XAML processing for certain classes. 属性将中.NET Framework 4.NET Framework 4自上而下行为的报告正规化。 UsableDuringInitializationAttributeThe UsableDuringInitializationAttribute attribute formalizes the reporting of the top-down behavior in .NET Framework 4.NET Framework 4.

构造函数

UsableDuringInitializationAttribute(Boolean)

初始化 UsableDuringInitializationAttribute 类的新实例。Initializes a new instance of the UsableDuringInitializationAttribute class.

属性

TypeId

在派生类中实现时,获取此 Attribute 的唯一标识符。When implemented in a derived class, gets a unique identifier for this Attribute.

(继承自 Attribute)
Usable

获取一个值,该值指示关联类在初始化期间是否可用。Gets a value that indicates whether the associated class is usable during initialization.

方法

Equals(Object)

返回一个值,该值指示此实例是否与指定的对象相等。Returns a value that indicates whether this instance is equal to a specified object.

(继承自 Attribute)
GetHashCode()

返回此实例的哈希代码。Returns the hash code for this instance.

(继承自 Attribute)
GetType()

获取当前实例的 TypeGets the Type of the current instance.

(继承自 Object)
IsDefaultAttribute()

在派生类中重写时,指示此实例的值是否是派生类的默认值。When overridden in a derived class, indicates whether the value of this instance is the default value for the derived class.

(继承自 Attribute)
Match(Object)

当在派生类中重写时,返回一个指示此实例是否等于指定对象的值。When overridden in a derived class, returns a value that indicates whether this instance equals a specified object.

(继承自 Attribute)
MemberwiseClone()

创建当前 Object 的浅表副本。Creates a shallow copy of the current Object.

(继承自 Object)
ToString()

返回一个表示当前对象的 string。Returns a string that represents the current object.

(继承自 Object)

显式界面实现

_Attribute.GetIDsOfNames(Guid, IntPtr, UInt32, UInt32, IntPtr)

将一组名称映射为对应的一组调度标识符。Maps a set of names to a corresponding set of dispatch identifiers.

(继承自 Attribute)
_Attribute.GetTypeInfo(UInt32, UInt32, IntPtr)

检索对象的类型信息,然后可以使用该信息获取接口的类型信息。Retrieves the type information for an object, which can be used to get the type information for an interface.

(继承自 Attribute)
_Attribute.GetTypeInfoCount(UInt32)

检索对象提供的类型信息接口的数量(0 或 1)。Retrieves the number of type information interfaces that an object provides (either 0 or 1).

(继承自 Attribute)
_Attribute.Invoke(UInt32, Guid, UInt32, Int16, IntPtr, IntPtr, IntPtr, IntPtr)

提供对某一对象公开的属性和方法的访问。Provides access to properties and methods exposed by an object.

(继承自 Attribute)

适用于

另请参阅