AttributeCallback 委托
[本文档仅供预览，在以后的发行版中可能会发生更改。包含的空白主题用作占位符。]
当某个类型需要特性时调用。
命名空间： Microsoft.Windows.Design.Metadata
程序集： Microsoft.Windows.Design.Extensibility（在 Microsoft.Windows.Design.Extensibility.dll 中）
语法
声明
Public Delegate Sub AttributeCallback ( _
builder As AttributeCallbackBuilder _
)
public delegate void AttributeCallback(
AttributeCallbackBuilder builder
)
public delegate void AttributeCallback(
AttributeCallbackBuilder^ builder
)
type AttributeCallback =
delegate of
builder:AttributeCallbackBuilder -> unit
JScript 不支持委托。
参数
- builder
类型：Microsoft.Windows.Design.Metadata.AttributeCallbackBuilder
可用于添加特性的 AttributeCallbackBuilder。AttributeCallbackBuilder 委托只能为请求元数据的类型生成特性。
备注
填充大特性表时，使用 AttributeCallback 委托。 通过使用回调模式，可以延迟填充特性表，直到设计人员需要某个类型的设计时元数据。
示例
下面的代码示例演示如何使用 AttributeCallbackBuilder 类创建和填充特性表。
using System;
using System.Collections;
using System.Collections.Generic;
using System.Text;
using System.ComponentModel;
using System.Reflection;
using System.Windows.Media;
using System.Windows.Controls;
using System.Windows;
using Microsoft.Windows.Design.Features;
using Microsoft.Windows.Design.Metadata;
// The ProvideMetadata assembly-level attribute indicates to designers
// that this assembly contains a class that provides an attribute table.
[assembly: ProvideMetadata(typeof(CustomControlLibrary.VisualStudio.Design.Metadata))]
namespace CustomControlLibrary.VisualStudio.Design
{
// Container for any general design-time metadata to initialize.
// Designers look for a type in the design-time assembly that
// implements IProvideAttributeTable. If found, designers instantiate
// this class and access its AttributeTable property automatically.
internal class Metadata : IProvideAttributeTable
{
// Accessed by the designer to register any design-time metadata.
public AttributeTable AttributeTable
{
get
{
AttributeTableBuilder builder = new AttributeTableBuilder();
// Build the attribute table by using the AttributeCallbackBuilder
// class. The attribute table is not populated until the designer
// needs it, which is more efficient for large attribute tables.
builder.AddCallback(
typeof(Button),
delegate(AttributeCallbackBuilder callbackBuilder)
{
callbackBuilder.AddCustomAttributes(
new DefaultPropertyAttribute("Content"));
// Apply the ReadOnlyAttribute to the Background property
// of the Button class.
callbackBuilder.AddCustomAttributes(
"Background",
new ReadOnlyAttribute(true));
});
return builder.CreateTable();
}
}
}
}
请参见
参考
Microsoft.Windows.Design.Metadata 命名空间