AttributeTable-Klasse

Článek
08/23/2008

Aktualisiert: November 2007

Eine Tabelle mit Metadatenattributen zum Definieren der Darstellung und des Verhaltens zur Entwurfszeit.

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

Syntax

'Declaration
Public NotInheritable Class AttributeTable
'Usage
Dim instance As AttributeTable

public sealed class AttributeTable

public ref class AttributeTable sealed

public final class AttributeTable

Hinweise

Verwenden Sie die AttributeTable-Klasse, um Metadatenattribute zur Entwurfszeit Windows Presentation Foundation (WPF)-Typen zuzuordnen.

Eine Attributtabelle ist im Wesentlichen ein schreibgeschütztes Wörterbuch, ihre Schlüssel und Werte werden jedoch getrennt berechnet. Es ist effizient, eine Attributtabelle abzufragen, wenn sie Attribute für einen bestimmten Typ enthält. Der tatsächliche Satz von Attributen wird bei Bedarf erstellt.

Um eine Attributtabelle zu erstellen, rufen Sie die CreateTable-Methode der AttributeTableBuilder-Klasse auf.

Beispiele

Das folgende Codebeispiel zeigt das Erstellen und das Füllen einer Attributtabelle. Weitere Informationen finden Sie unter Exemplarische Vorgehensweise: Erstellen eines Entwurfszeitadorners.

Imports System
Imports System.Collections
Imports System.Collections.Generic
Imports System.ComponentModel
Imports System.Reflection
Imports System.Text
Imports System.Windows.Media
Imports System.Windows.Controls
Imports System.Windows

Imports Microsoft.Windows.Design
Imports Microsoft.Windows.Design.Features
Imports Microsoft.Windows.Design.Metadata

' 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.

Friend Class Metadata
    Implements IRegisterMetadata

    ' Called by the designer to register any design-time metadata.
    Public Sub Register() Implements IRegisterMetadata.Register
        Dim builder As New AttributeTableBuilder()

        ' Apply the ReadOnlyAttribute to the Background property 
        ' of the Button class.
        builder.AddCustomAttributes(GetType(Button), "Background", New ReadOnlyAttribute(True))

        Dim attributes As AttributeTable = builder.CreateTable()

        MetadataStore.AddAttributeTable(attributes)

        Dim hasCustomAttributes As Boolean = attributes.ContainsAttributes(GetType(Button))

        Dim types As IEnumerable(Of Type) = attributes.AttributedTypes

        ' The following code shows how to retrieve custom attributes
        ' using the GetCustomAttributes method overloads.

        Dim attrs0 As IEnumerable = attributes.GetCustomAttributes(GetType(Button))

        Dim attrs1 As IEnumerable = attributes.GetCustomAttributes(GetType(Button), "Background")

        Dim properties As PropertyDescriptorCollection = TypeDescriptor.GetProperties(GetType(Button))
        Dim pd As PropertyDescriptor = properties("Background")
        Dim attrs2 As IEnumerable = attributes.GetCustomAttributes(GetType(Button), pd)

        Dim attrs3 As IEnumerable = attributes.GetCustomAttributes(GetType(Button), Button.BackgroundProperty)

        Dim members As MemberInfo() = GetType(Button).GetMembers()
        Dim i As Integer
        For i = 0 To members.Length
            If members(i).Name = "Background" Then
                Dim attrs4 As IEnumerable = attributes.GetCustomAttributes(GetType(Button), members(i))
            End If
        Next i

    End Sub

End Class

using System;
using System.Collections;
using System.Collections.Generic;
using System.ComponentModel;
using System.Reflection;
using System.Text;
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();

            // Apply the ReadOnlyAttribute to the Background property 
            // of the Button class.
            builder.AddCustomAttributes(
                typeof(Button),
                "Background",
                new ReadOnlyAttribute(true)  );

            AttributeTable attributes = builder.CreateTable();

            MetadataStore.AddAttributeTable(attributes);

            bool hasCustomAttributes = attributes.ContainsAttributes(typeof(Button));

            IEnumerable<Type> types = attributes.AttributedTypes;

            // The following code shows how to retrieve custom attributes
            // using the GetCustomAttributes method overloads.

            IEnumerable attrs0 = attributes.GetCustomAttributes(typeof(Button));

            IEnumerable attrs1 = attributes.GetCustomAttributes(
                typeof(Button), 
                "Background");

            PropertyDescriptorCollection properties = 
                TypeDescriptor.GetProperties(typeof(Button));
            PropertyDescriptor pd = properties["Background"];
            IEnumerable attrs2 = attributes.GetCustomAttributes(typeof(Button), pd);

            IEnumerable attrs3 = attributes.GetCustomAttributes(
                typeof(Button),
                Button.BackgroundProperty);

            MemberInfo[] members = typeof(Button).GetMembers();
            for (int i = 0; i < members.Length; i++)
            {
                if (members[i].Name == "Background")
                {
                    IEnumerable attrs4 = attributes.GetCustomAttributes(
                        typeof(Button), 
                        members[i]);
                }
            }
        }
    }
}

Vererbungshierarchie

System.Object
Microsoft.Windows.Design.Metadata.AttributeTable

Threadsicherheit

Alle öffentlichen static (Shared in Visual Basic)-Member dieses Typs sind threadsicher. Bei Instanzmembern ist die Threadsicherheit nicht gewährleistet.