AttributeCallbackBuilder Class

An instance of this class is passed to callback delegates to lazily populate the attributes for a type.

Inheritance Hierarchy

System.Object
  Microsoft.Windows.Design.Metadata.AttributeCallbackBuilder

Namespace:  Microsoft.Windows.Design.Metadata
Assembly:  Microsoft.Windows.Design.Extensibility (in Microsoft.Windows.Design.Extensibility.dll)

Syntax

'Declaration
Public NotInheritable Class AttributeCallbackBuilder

public sealed class AttributeCallbackBuilder

public ref class AttributeCallbackBuilder sealed

[<Sealed>]
type AttributeCallbackBuilder =  class end

public final class AttributeCallbackBuilder

The AttributeCallbackBuilder type exposes the following members.

Properties

	Name	Description
	CallbackType	Gets the type this callback is being invoked for.

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Methods

	Name	Description
	AddCustomAttributes(array<Attribute[])	Adds the contents of the specified attributes to this builder.
	AddCustomAttributes(String, array<Attribute[])	Adds attributes to the member with the specified name.
	Equals	Determines whether the specified Object is equal to the current Object. (Inherited from Object.)
	Finalize	Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)
	GetHashCode	Serves as a hash function for a particular type. (Inherited from Object.)
	GetType	Gets the Type of the current instance. (Inherited from Object.)
	MemberwiseClone	Creates a shallow copy of the current Object. (Inherited from Object.)
	ToString	Returns a string that represents the current object. (Inherited from Object.)

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Remarks

Use the AttributeCallbackBuilder to populate an AttributeTable on demand. This is especially important for attribute tables that hold many attributes. If you are specifying only a few attributes for a type, use the AttributeTableBuilder by itself.

Using the delegate format, no attributes are constructed until metadata for the target type is requested by the designer. The AttributeTableBuilder transfers this callback information into the AttributeTable and preserves it. Therefore, these callback delegates are only invoked on demand. Once invoked, their results are cached by the AttributeTable.

Enable on-demand attribute creation by using the AddCallback method.

Examples

The following code example shows how to create and populate an attribute table by using the AttributeCallbackBuilder class.

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();
            }
        }
    }
}

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.

See Also

Reference

Microsoft.Windows.Design.Metadata Namespace

AttributeTableBuilder

AddCallback

AttributeTable

Other Resources

Walkthrough: Creating a Design-time Adorner