AttributeCallbackBuilder 類別

發行項
08/21/2008

更新：2007 年 11 月

這個類別的執行個體會傳遞至回呼委派，以延緩填入型別的屬性。

命名空間： Microsoft.Windows.Design.Metadata
組件： Microsoft.Windows.Design (在 Microsoft.Windows.Design.dll 中)

語法

Public NotInheritable Class AttributeCallbackBuilder

Dim instance As AttributeCallbackBuilder

public sealed class AttributeCallbackBuilder

public ref class AttributeCallbackBuilder sealed

public final class AttributeCallbackBuilder

備註

您可以使用 AttributeCallbackBuilder 視需要填入 AttributeTable。對於存放許多屬性的屬性表格而言，這特別重要。如果您只要為型別指定少數幾個屬性，請單獨使用 AttributeTableBuilder。

如果使用委派格式，那麼直到設計工具要求目標型別的中繼資料為止，都不會建構任何屬性。AttributeTableBuilder 會將這項回呼資訊轉換成 AttributeTable 並加以保存。因此，只在有需要時才會叫用這些回呼委派。一旦叫用這些回呼委派，AttributeTable 就會快取這些回呼委派的結果。

您可以使用 AddCallback 方法，啟用依需要建立屬性的功能。

範例

在下列程式碼範例中，會說明如何使用 AttributeCallbackBuilder 類別建立屬性表格，並在其中填入內容。

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;

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 IRegisterMetadata. If found, designers instantiate 
    // this class and call its Register() method automatically.
    internal class Metadata : IRegisterMetadata
    {
        // Called by the designer to register any design-time metadata.
        public void Register()
        {
            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));

                PropertyDescriptorCollection properties =
                    TypeDescriptor.GetProperties(typeof(Button));
                PropertyDescriptor pd = properties["Foreground"];
                callbackBuilder.AddCustomAttributes(
                    pd,
                    new ReadOnlyAttribute(true));

                callbackBuilder.AddCustomAttributes(
                   Button.WidthProperty,
                   new TypeConverterAttribute(typeof(LengthConverter)),
                   new DescriptionAttribute("This is the width"));

                MemberInfo[] members = typeof(Button).GetMember("Height");
                callbackBuilder.AddCustomAttributes(
                    members[0],
                    new ReadOnlyAttribute(true));
            });

            MetadataStore.AddAttributeTable(builder.CreateTable());
        }
    }
}