How to: Create a Custom Feature Connector

The following code examples show how to implement a custom feature connector. For a complete solution, see the Feature Connector sample from the WPF Designer Extensibility Samples site.

Example

The following code example shows how to derive from the FeatureConnector<TFeatureProviderType> class to connect a custom feature provider named DiagnosticsMenuProvider with a custom service named IDiagnosticsService.

Imports System
Imports System.Windows

' The DemoButton control provides a button that
' has custom design-time behavior. 
Public Class DemoButton
    Inherits System.Windows.Controls.Button
End Class
using System;
using System.Windows;

namespace DemoControlLibrary
{
    // The DemoButton control provides a button that
    // has custom design-time behavior. 
    public class DemoButton : System.Windows.Controls.Button 
    {

    }
}
Imports System
Imports Microsoft.Windows.Design.Features
Imports Microsoft.Windows.Design.Interaction

' The DiagnosticsMenuProvider class adds a context menu item
' that displays a dialog box listing the currently running and 
' pending feature connectors. 
<FeatureConnector(GetType(DiagnosticsFeatureConnector))>  _
Public Class DiagnosticsMenuProvider
    Inherits PrimarySelectionContextMenuProvider

    Public Sub New() 
        Dim action As New MenuAction("Feature Diagnostics...")

        AddHandler action.Execute, AddressOf action_Execute 

        Items.Add(action)    
    End Sub

    Sub action_Execute(ByVal sender As Object, ByVal e As MenuActionEventArgs) 
        Dim service As IDiagnosticsService = e.Context.Services.GetRequiredService(Of IDiagnosticsService)()

        service.ShowWindow()

    End Sub

End Class

' The IDiagnosticsService specifies a simple interface for showing
' a FeatureManagerDiagnostics window.
Interface IDiagnosticsService
    Sub ShowWindow() 
End Interface

' The DiagnosticsFeatureConnector publishes the IDiagnosticsService. 
Class DiagnosticsFeatureConnector
    Inherits FeatureConnector(Of DiagnosticsMenuProvider)
    Implements IDiagnosticsService

    Dim fmdWindow As FeatureManagerDiagnostics

    Public Sub New(ByVal manager As FeatureManager) 
        MyBase.New(manager)

        Context.Services.Publish(Of IDiagnosticsService)(Me)

    End Sub

    ' The showWindow method creates a FeatureManagerDiagnostics
    ' window and shows it.
    Public Sub ShowWindow() Implements IDiagnosticsService.ShowWindow

        If fmdWindow IsNot Nothing Then

            ' Show the FeatureManagerDiagnostics window.
            fmdWindow.Show()

            ' Activate the 
            fmdWindow.Activate()

        Else

            fmdWindow = New FeatureManagerDiagnostics()
            fmdWindow.Initialize(Manager)
            AddHandler fmdWindow.Closed, AddressOf fmdWindow_Closed
            fmdWindow.Show()

        End If

    End Sub

    Sub fmdWindow_Closed(ByVal sender As Object, ByVal e As EventArgs)

        fmdWindow = Nothing

    End Sub

End Class
using System;
using Microsoft.Windows.Design.Features;
using Microsoft.Windows.Design.Interaction;

namespace DemoControlLibrary.VisualStudio.Design
{
    // The DiagnosticsMenuProvider class adds a context menu item
    // that displays a dialog box listing the currently running and 
    // pending feature connectors. 
    [FeatureConnector(typeof(DiagnosticsFeatureConnector))]
    public class DiagnosticsMenuProvider : PrimarySelectionContextMenuProvider 
    {
        public DiagnosticsMenuProvider() 
        {
            MenuAction action = new MenuAction("Feature Diagnostics...");

            action.Execute += new EventHandler<MenuActionEventArgs>(action_Execute); 

            Items.Add(action);
        }

        void action_Execute(object sender, MenuActionEventArgs e)
        {
            IDiagnosticsService service = 
                e.Context.Services.GetRequiredService<IDiagnosticsService>();

            service.ShowWindow();
        }
    }

    // The IDiagnosticsService specifies a simple interface for showing
    // a FeatureManagerDiagnostics window.
    interface IDiagnosticsService 
    {
        void ShowWindow();
    }

    // The DiagnosticsFeatureConnector publishes the IDiagnosticsService. 
    class DiagnosticsFeatureConnector : FeatureConnector<DiagnosticsMenuProvider>,
        IDiagnosticsService 
    {
        FeatureManagerDiagnostics fmdWindow;

        public DiagnosticsFeatureConnector(FeatureManager manager)
            : base(manager) 
        {
            Context.Services.Publish<IDiagnosticsService>(this);
        }

        #region IDiagnosticsService Members

        // The showWindow method creates a FeatureManagerDiagnostics
        // window and shows it.
        public void ShowWindow() 
        {
            if (fmdWindow != null) 
            {
                fmdWindow.Show();
                fmdWindow.Activate();
            }
            else 
            {
                fmdWindow = new FeatureManagerDiagnostics();
                fmdWindow.Initialize(Manager);
                fmdWindow.Closed += new EventHandler(fmdWindow_Closed); 
                fmdWindow.Show();
            }
        }

        void fmdWindow_Closed(object sender, EventArgs e)
        {
            fmdWindow = null; 
        }

        #endregion
    }
}
Imports System
Imports System.Collections.Generic
Imports System.Text
Imports System.Windows
Imports System.Windows.Controls
Imports System.Windows.Data
Imports System.Windows.Documents
Imports System.Windows.Input
Imports System.Windows.Media
Imports System.Windows.Media.Imaging
Imports System.Windows.Shapes

Imports Microsoft.Windows.Design.Features

' The FeatureManagerDiagnostics class implements a window
' that displays the running and pending feature connectors.
Partial Public Class FeatureManagerDiagnostics
    Inherits Window

    Private featManager As FeatureManager

    Public Sub New()
        InitializeComponent()

    End Sub

    Public Sub Initialize(ByVal manager As FeatureManager)
        featManager = manager
        Bind()
    End Sub

    Private Sub OnRefreshClick(ByVal sender As Object, ByVal e As RoutedEventArgs)
        Bind()
    End Sub

    ' Binds the activatedFeatures and pendingFeatures controls
    ' the FeatureManager's RunningConnectors and PendingConnectors\
    ' properties.
    Private Sub Bind()
        activatedFeatures.Items.Clear()
        pendingFeatures.Items.Clear()

        Dim info As FeatureConnectorInformation
        For Each info In featManager.RunningConnectors
            activatedFeatures.Items.Add(info)
        Next info

        For Each info In featManager.PendingConnectors
            pendingFeatures.Items.Add(info)
        Next info

    End Sub

End Class
using System;
using System.Collections.Generic;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Shapes;

using Microsoft.Windows.Design.Features;

namespace DemoControlLibrary.VisualStudio.Design
{
    // The FeatureManagerDiagnostics class implements a window
    // that displays the running and pending feature connectors.
    public partial class FeatureManagerDiagnostics : Window 
    {
        private FeatureManager featManager;

        public FeatureManagerDiagnostics() 
        {
            InitializeComponent();
        }

        public void Initialize(FeatureManager manager) 
        {
            featManager = manager;
            Bind();
        }

        private void OnRefreshClick(object sender, RoutedEventArgs e) 
        {
            Bind();
        }

        // Binds the activatedFeatures and pendingFeatures controls
        // the FeatureManager's RunningConnectors and PendingConnectors\
        // properties.
        private void Bind() 
        {
            activatedFeatures.Items.Clear();
            pendingFeatures.Items.Clear();

            foreach (FeatureConnectorInformation info in 
                featManager.RunningConnectors) 
            {
                activatedFeatures.Items.Add(info);
            }

            foreach (FeatureConnectorInformation info in 
                featManager.PendingConnectors) 
            {
                pendingFeatures.Items.Add(info);
            }
        }
    }
}
<Window 
  xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
  xmlns:l="clr-namespace:DemoControlLibrary.VisualStudio.Design" 
  x:Class="DemoControlLibrary.VisualStudio.Design.FeatureManagerDiagnostics"
  Title="Feature Diagnostics" WindowStartupLocation="CenterOwner" SizeToContent="Manual" Height="316" Width="448" >

  <Window.Resources>
    <Style x:Key="HeaderStyle" TargetType="HeaderedItemsControl">

      <Setter Property="Template">
        <Setter.Value>
          <ControlTemplate TargetType="HeaderedItemsControl">
            <StackPanel>
              <Border Padding="5" Background="#FFDDDDDD">
                <CheckBox IsChecked="True" FontWeight="Bold" Name="Expander" Content="{TemplateBinding Header}"/>
              </Border>
              <Border Padding="5" Name="ItemsHost">
                <ItemsPresenter/>
              </Border>
            </StackPanel>

            <ControlTemplate.Triggers>
              <Trigger SourceName="Expander" Property="ToggleButton.IsChecked" Value="true">
                <Setter TargetName="ItemsHost" Property="Visibility" Value="Visible" />
              </Trigger>
              <Trigger SourceName="Expander" Property="ToggleButton.IsChecked" Value="false">
                <Setter TargetName="ItemsHost" Property="Visibility" Value="Collapsed" />
              </Trigger>
            </ControlTemplate.Triggers>
          </ControlTemplate>
        </Setter.Value>
      </Setter>
    </Style>

    <DataTemplate x:Key="FeatureInfo" DataType="l:FeatureConnectorInformation">
      <StackPanel>
        <Border BorderBrush="{x:Static SystemColors.ActiveCaptionBrush}" BorderThickness="0,0,0,1">
          <TextBlock FontWeight="Bold" Text="{Binding Path=FeatureConnectorType}" />
        </Border>
        <Border Padding="15,0,0,5" TextElement.FontSize = "10">
          <StackPanel>
            <TextBlock FontWeight="Bold" Text="Required Services" />
            <Border Padding="10,0,0,5">
              <ItemsControl ItemsSource="{Binding Path=RequiredServices}" />
            </Border>
            <TextBlock FontWeight="Bold" Text="Required Context Items" />
            <Border Padding="10,0,0,5">
              <ItemsControl ItemsSource="{Binding Path=RequiredItems}" />
            </Border>
          </StackPanel>
        </Border>
      </StackPanel>
    </DataTemplate>

    <DataTemplate x:Key="PendingFeatureInfo" DataType="l:FeatureConnectorInformation">
      <StackPanel>
        <Border BorderBrush="{x:Static SystemColors.ActiveCaptionBrush}" BorderThickness="0,0,0,1">
          <TextBlock FontWeight="Bold" Text="{Binding Path=FeatureConnectorType}" />
        </Border>
        <Border Padding="15,0,0,5" TextElement.FontSize = "10">
          <StackPanel>
            <TextBlock FontWeight="Bold" Text="Missing Services" />
            <Border Padding="10,0,0,5">
              <ItemsControl ItemsSource="{Binding Path=PendingServices}" />
            </Border>
            <TextBlock FontWeight="Bold" Text="Missing Context Items" />
            <Border Padding="10,0,0,5">
              <ItemsControl ItemsSource="{Binding Path=PendingItems}" />
            </Border>
          </StackPanel>
        </Border>
      </StackPanel>
    </DataTemplate>
  </Window.Resources>

  <Grid>
    <ScrollViewer Margin="0,0,0,36" VerticalScrollBarVisibility="Auto">
      <StackPanel>
        <HeaderedItemsControl Name="pendingFeatures" Style="{StaticResource HeaderStyle}" Header="Pending Features" ItemTemplate="{StaticResource PendingFeatureInfo}" />
        <HeaderedItemsControl Name="activatedFeatures" Style="{StaticResource HeaderStyle}" Header="Activated Features" ItemTemplate="{StaticResource FeatureInfo}" />
      </StackPanel>
    </ScrollViewer>
    <Button Height="23" Margin="0,0,8,7" Click="OnRefreshClick" VerticalAlignment="Bottom" HorizontalAlignment="Right" Width="75">Refresh</Button>
  </Grid>
</Window>
Imports System
Imports DemoControlLibrary

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

' The ProvideMetadata assembly-level attribute indicates to designers
' that this assembly contains a class that provides an attribute table. 
<Assembly: ProvideMetadata(GetType(DemoControlLibrary.VisualStudio.Design.Metadata))> 

' 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.
Friend Class Metadata
    Implements IProvideAttributeTable

    ' Accessed by the designer to register any design-time metadata.
    Public ReadOnly Property AttributeTable() As AttributeTable _
        Implements IProvideAttributeTable.AttributeTable
        Get
            Dim builder As New AttributeTableBuilder()
            InitializeAttributes(builder)

            Return builder.CreateTable()
        End Get
    End Property

    Private Sub InitializeAttributes(ByVal builder As AttributeTableBuilder) 
        builder.AddCallback(GetType(DemoButton), AddressOf AddButtonAttributes)

    End Sub

    Private Sub AddButtonAttributes(ByVal builder As AttributeCallbackBuilder) 
        builder.AddCustomAttributes(New FeatureAttribute(GetType(DiagnosticsMenuProvider)))
    End Sub
End Class
using System;
using DemoControlLibrary;

using Microsoft.Windows.Design.Metadata;
using Microsoft.Windows.Design.Features;

// The ProvideMetadata assembly-level attribute indicates to designers
// that this assembly contains a class that provides an attribute table. 
[assembly: ProvideMetadata(typeof(DemoControlLibrary.VisualStudio.Design.Metadata))]
namespace DemoControlLibrary.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 
    {
        public AttributeTable AttributeTable
        {
            get 
            {
                AttributeTableBuilder builder = new AttributeTableBuilder();
                InitializeAttributes(builder);
                return builder.CreateTable();
            }
        }

        private void InitializeAttributes(AttributeTableBuilder builder) 
        {
            builder.AddCallback(typeof(DemoButton), AddButtonAttributes);
        }

        private void AddButtonAttributes(AttributeCallbackBuilder builder)
        {
            builder.AddCustomAttributes(
                new FeatureAttribute(typeof(DiagnosticsMenuProvider))
            );
        }
    }
}
<Window x:Class="DemoApplication.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:c="clr-namespace:DemoControlLibrary;assembly=DemoControlLibrary" 
    Title="Window1" Height="300" Width="300">
    <Grid>
        <c:DemoButton />
    </Grid>
</Window>

Compiling the Code

For a complete solution, see the Feature Connector sample from the WPF Designer Extensibility Samples site.

See Also

Tasks

Walkthrough: Creating a Design-time Adorner

Reference

FeatureManager

FeatureProvider

FeatureConnector<TFeatureProviderType>

FeatureConnectorAttribute

Concepts

Feature Providers and Feature Connectors

Other Resources

WPF Designer Extensibility

WPF Designer Extensibility Samples