AttributeTableBuilder.AddCallback 方法

项目
09/04/2008

更新：2007 年 11 月

添加一个在需要指定类型的元数据时调用的回调。

命名空间： Microsoft.Windows.Design.Metadata
程序集： Microsoft.Windows.Design（在 Microsoft.Windows.Design.dll 中）

语法

声明
Public Sub AddCallback ( _
    type As Type, _
    callback As AttributeCallback _
)
用法
Dim instance As AttributeTableBuilder
Dim type As Type
Dim callback As AttributeCallback

instance.AddCallback(type, callback)

public void AddCallback(
    Type type,
    AttributeCallback callback
)

public:
void AddCallback(
    Type^ type, 
    AttributeCallback^ callback
)

public function AddCallback(
    type : Type, 
    callback : AttributeCallback
)

参数

type
类型：System.Type

要向其添加元数据属性的类型。

callback
类型：Microsoft.Windows.Design.Metadata.AttributeCallback

向 Type 添加元数据的 AttributeCallback。

备注

Callback 可在需要时向属性表中添加元数据，这比在创建表时添加元数据更为高效。

在生成较大的属性表时，请将 AddCallback 方法用于 AttributeCallbackBuilder 类。

示例

下面的代码示例演示如何使用 AddCallback 方法和 AttributeTableBuilder 类创建和填充属性表。此代码示例摘自为 AttributeCallbackBuilder 类提供的一个更大的示例。

// 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());
    }
}