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AdornerProvider Class

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A feature provider that you can add to a class to automatically add adorners to the designer surface.

Inheritance Hierarchy

System.Object
  Microsoft.Windows.Design.Features.FeatureProvider
    Microsoft.Windows.Design.Interaction.AdornerProvider
      Microsoft.Windows.Design.Interaction.PrimarySelectionAdornerProvider

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

Syntax

'Declaration
Public MustInherit Class AdornerProvider _
    Inherits FeatureProvider

public abstract class AdornerProvider : FeatureProvider

public ref class AdornerProvider abstract : public FeatureProvider

[<AbstractClass>]
type AdornerProvider =  
    class
        inherit FeatureProvider
    end

public abstract class AdornerProvider extends FeatureProvider

The AdornerProvider type exposes the following members.

Constructors

  Name Description
Protected method AdornerProvider Initializes a new instance of the AdornerProvider class.

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Properties

  Name Description
Public property Adorners Gets the collection of adorners that are provided by this adorner provider.
Public property AdornersVisible Gets or sets the visibility of a set of adorners.
Protected property Context Gets the editing context that activated this adorner provider.

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Methods

  Name Description
Protected method Activate Called when adorners are requested for the first time by the designer.
Protected method Deactivate Called when an adorner provider is about to be discarded by the designer.
Public method Equals Determines whether the specified Object is equal to the current Object. (Inherited from Object.)
Protected method Finalize Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)
Public method GetHashCode Serves as a hash function for a particular type. (Inherited from Object.)
Public method GetType Gets the Type of the current instance. (Inherited from Object.)
Public method IsToolSupported Gets a value indicating if the adorner provider supports the provided Tool.
Protected method MemberwiseClone Creates a shallow copy of the current Object. (Inherited from Object.)
Public method ToString Returns a string that represents the current object. (Inherited from Object.)

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Remarks

Adorners are added according to an AdornerProvider's policy. You can add a policy to an AdornerProvider by adding a UsesItemPolicyAttribute to the class definition.

To add adorners that appear during selection, derive from PrimarySelectionAdornerProvider as it already has the correct policy attribute applied.

Examples

The following code example shows how to derive a custom type from the PrimarySelectionAdornerProvider class. The custom type creates an AdornerPanel to host a Slider control, which is used at design-time to set the Background property of the adorned control. For more information, see Walkthrough: Creating a Design-time Adorner.

Imports System
Imports System.Collections.Generic
Imports System.Text
Imports System.Windows.Input
Imports System.Windows
Imports System.Windows.Automation
Imports System.Windows.Controls
Imports System.Windows.Media
Imports System.Windows.Shapes
Imports Microsoft.Windows.Design.Interaction
Imports Microsoft.Windows.Design.Model

Namespace CustomControlLibrary.VisualStudio.Design

    ' The following class implements an adorner provider for the 
    ' adorned control. The adorner is a slider control, which 
    ' changes the Background opacity of the adorned control.
    Class OpacitySliderAdornerProvider
        Inherits PrimarySelectionAdornerProvider
        Private adornedControlModel As ModelItem
        Private batchedChange As ModelEditingScope
        Private opacitySlider As Slider
        Private opacitySliderAdornerPanel As AdornerPanel

        Public Sub New()
            opacitySlider = New Slider()
        End Sub

        ' The following method is called when the adorner is activated.
        ' It creates the adorner control, sets up the adorner panel,
        ' and attaches a ModelItem to the adorned control.
        Protected Overrides Sub Activate(ByVal item As ModelItem)

            ' Save the ModelItem and hook into when it changes.
            ' This enables updating the slider position when 
            ' a new Background value is set.
            adornedControlModel = item
            AddHandler adornedControlModel.PropertyChanged, AddressOf AdornedControlModel_PropertyChanged

            ' Setup the slider's min and max values.
            opacitySlider.Minimum = 0
            opacitySlider.Maximum = 1

            ' Setup the adorner panel.
            ' All adorners are placed in an AdornerPanel
            ' for sizing and layout support.
            Dim myPanel = Me.Panel

            ' The slider extends the full width of the control it adorns.
            AdornerPanel.SetAdornerHorizontalAlignment( _
                opacitySlider, _
                AdornerHorizontalAlignment.Stretch)

            ' Position the adorner above the control it adorns.
            AdornerPanel.SetAdornerVerticalAlignment( _
                opacitySlider, _
                AdornerVerticalAlignment.OutsideTop)

            ' Position the adorner 5 pixels above the control. 
            AdornerPanel.SetAdornerMargin( _
                opacitySlider, _
                New Thickness(0, 0, 0, 5))

            ' Initialize the slider when it is loaded.
            AddHandler opacitySlider.Loaded, AddressOf slider_Loaded

            ' Handle the value changes of the slider control.
            AddHandler opacitySlider.ValueChanged, AddressOf slider_ValueChanged

            AddHandler opacitySlider.PreviewMouseLeftButtonUp, _
                AddressOf slider_MouseLeftButtonUp

            AddHandler opacitySlider.PreviewMouseLeftButtonDown, _
                AddressOf slider_MouseLeftButtonDown

            MyBase.Activate(item)

        End Sub

        ' The Panel utility property demand-creates the 
        ' adorner panel and adds it to the provider's 
        ' Adorners collection.
        Public ReadOnly Property Panel() As AdornerPanel
            Get
                If Me.opacitySliderAdornerPanel Is Nothing Then
                    Me.opacitySliderAdornerPanel = New AdornerPanel()

                    ' Add the adorner to the adorner panel.
                    Me.opacitySliderAdornerPanel.Children.Add(opacitySlider)

                    ' Add the panel to the Adorners collection.
                    Adorners.Add(opacitySliderAdornerPanel)
                End If

                Return Me.opacitySliderAdornerPanel
            End Get
        End Property


        ' The following method deactivates the adorner.
        Protected Overrides Sub Deactivate()
            RemoveHandler adornedControlModel.PropertyChanged, _
                AddressOf AdornedControlModel_PropertyChanged
            MyBase.Deactivate()

        End Sub

        ' The following method handles the PropertyChanged event.
        ' It updates the slider control's value if the adorned control's 
        ' Background property changed,
        Sub AdornedControlModel_PropertyChanged( _
            ByVal sender As Object, _
            ByVal e As System.ComponentModel.PropertyChangedEventArgs)

            If e.PropertyName = "Background" Then
                opacitySlider.Value = GetCurrentOpacity()
            End If

        End Sub

        ' The following method handles the Loaded event.
        ' It assigns the slider control's initial value.
        Sub slider_Loaded(ByVal sender As Object, ByVal e As RoutedEventArgs)

            opacitySlider.Value = GetCurrentOpacity()

        End Sub

        ' The following method handles the MouseLeftButtonDown event.
        ' It calls the BeginEdit method on the ModelItem which represents 
        ' the adorned control.
        Sub slider_MouseLeftButtonDown( _
            ByVal sender As Object, _
            ByVal e As System.Windows.Input.MouseButtonEventArgs)

            batchedChange = adornedControlModel.BeginEdit()

        End Sub

        ' The following method handles the MouseLeftButtonUp event.
        ' It commits any changes made to the ModelItem which represents the
        ' the adorned control.
        Sub slider_MouseLeftButtonUp( _
            ByVal sender As Object, _
            ByVal e As System.Windows.Input.MouseButtonEventArgs)

            If Not (batchedChange Is Nothing) Then
                batchedChange.Complete()
                batchedChange.Dispose()
                batchedChange = Nothing
            End If

        End Sub

        ' The following method handles the slider control's 
        ' ValueChanged event. It sets the value of the 
        ' Background opacity by using the ModelProperty type.
        Sub slider_ValueChanged( _
            ByVal sender As Object, _
            ByVal e As RoutedPropertyChangedEventArgs(Of Double))

            If (True) Then
                Dim newOpacityValue As Double = e.NewValue

                ' During setup, don't make a value local and set the opacity.
                If newOpacityValue = GetCurrentOpacity() Then
                    Return
                End If

                ' Access the adorned control's Background property
                ' by using the ModelProperty type.
                Dim backgroundProperty As ModelProperty = _
                    adornedControlModel.Properties("Background")
                If Not backgroundProperty.IsSet Then
                    ' If the value isn't local, make it local 
                    ' before setting a sub-property value.
                    backgroundProperty.SetValue(backgroundProperty.ComputedValue)
                End If

                ' Set the Opacity property on the Background Brush.
                backgroundProperty.Value.Properties("Opacity").SetValue(newOpacityValue)
            End If
        End Sub

        ' This utility method gets the adorned control's
        ' Background brush by using the ModelItem.
        Function GetCurrentOpacity() As Double

            Dim backgroundBrushComputedValue As Brush = _
            CType(adornedControlModel.Properties("Background").ComputedValue,  _
            Brush)

            Return backgroundBrushComputedValue.Opacity

        End Function
    End Class
End Namespace

using System;
using System.Collections.Generic;
using System.Text;
using System.Windows.Input;
using System.Windows;
using System.Windows.Automation;
using System.Windows.Controls;
using System.Windows.Media;
using System.Windows.Shapes;
using Microsoft.Windows.Design.Interaction;
using Microsoft.Windows.Design.Model;

namespace CustomControlLibrary.VisualStudio.Design
{
    // The following class implements an adorner provider for the 
    // adorned control. The adorner is a slider control, which 
    // changes the Background opacity of the adorned control.
    class OpacitySliderAdornerProvider : PrimarySelectionAdornerProvider
    {
        private ModelItem adornedControlModel;
        private ModelEditingScope batchedChange;
        private Slider opacitySlider;
        private AdornerPanel opacitySliderAdornerPanel;

        public OpacitySliderAdornerProvider()
        {
            opacitySlider = new Slider();
        }

        // The following method is called when the adorner is activated.
        // It creates the adorner control, sets up the adorner panel,
        // and attaches a ModelItem to the adorned control.
        protected override void Activate(ModelItem item)
        {
            // Save the ModelItem and hook into when it changes.
            // This enables updating the slider position when 
            // a new Background value is set.
            adornedControlModel = item;
            adornedControlModel.PropertyChanged += 
                new System.ComponentModel.PropertyChangedEventHandler(
                    AdornedControlModel_PropertyChanged);

            // Setup the slider's min and max values.
            opacitySlider.Minimum = 0;
            opacitySlider.Maximum = 1;

            // Setup the adorner panel.
            // All adorners are placed in an AdornerPanel
            // for sizing and layout support.
            AdornerPanel myPanel = this.Panel;

            // The slider extends the full width of the control it adorns.
            AdornerPanel.SetAdornerHorizontalAlignment( 
                opacitySlider, 
                AdornerHorizontalAlignment.Stretch);

            // Position the adorner above the control it adorns.
            AdornerPanel.SetAdornerVerticalAlignment(
                opacitySlider, 
                AdornerVerticalAlignment.OutsideTop);

            // Position the adorner 5 pixels above the control. 
            AdornerPanel.SetAdornerMargin(
                opacitySlider, 
                new Thickness(0, 0, 0, 5));

            // Initialize the slider when it is loaded.
            opacitySlider.Loaded += new RoutedEventHandler(slider_Loaded);

            // Handle the value changes of the slider control.
            opacitySlider.ValueChanged += 
                new RoutedPropertyChangedEventHandler<double>(
                    slider_ValueChanged);

            opacitySlider.PreviewMouseLeftButtonUp += 
                new System.Windows.Input.MouseButtonEventHandler(
                    slider_MouseLeftButtonUp);

            opacitySlider.PreviewMouseLeftButtonDown += 
                new System.Windows.Input.MouseButtonEventHandler(
                    slider_MouseLeftButtonDown);

            base.Activate(item);
        }

        // The Panel utility property demand-creates the 
        // adorner panel and adds it to the provider's 
        // Adorners collection.
        public AdornerPanel Panel 
        { 
            get
            {
                if (this.opacitySliderAdornerPanel == null)
                {
                    opacitySliderAdornerPanel = new AdornerPanel();

                    opacitySliderAdornerPanel.Children.Add(opacitySlider);

                    // Add the panel to the Adorners collection.
                    Adorners.Add(opacitySliderAdornerPanel);
                }

                return this.opacitySliderAdornerPanel;
            } 
        }


        // The following method deactivates the adorner.
        protected override void Deactivate()
        {
            adornedControlModel.PropertyChanged -= 
                new System.ComponentModel.PropertyChangedEventHandler(
                    AdornedControlModel_PropertyChanged);
            base.Deactivate();
        }

        // The following method handles the PropertyChanged event.
        // It updates the slider control's value if the adorned control's 
        // Background property changed,
        void AdornedControlModel_PropertyChanged(
            object sender, 
            System.ComponentModel.PropertyChangedEventArgs e)
        {
            if (e.PropertyName == "Background")
            {   
                opacitySlider.Value = GetCurrentOpacity();
            }
        }

        // The following method handles the Loaded event.
        // It assigns the slider control's initial value.
        void slider_Loaded(object sender, RoutedEventArgs e)
        {   
            opacitySlider.Value = GetCurrentOpacity();
        }

        // The following method handles the MouseLeftButtonDown event.
        // It calls the BeginEdit method on the ModelItem which represents 
        // the adorned control.
        void slider_MouseLeftButtonDown(
            object sender, 
            System.Windows.Input.MouseButtonEventArgs e)
        {
            batchedChange = adornedControlModel.BeginEdit();
        }

        // The following method handles the MouseLeftButtonUp event.
        // It commits any changes made to the ModelItem which represents the
        // the adorned control.
        void slider_MouseLeftButtonUp(
            object sender, 
            System.Windows.Input.MouseButtonEventArgs e)
        {
            if (batchedChange != null)
            {
                batchedChange.Complete();
                batchedChange.Dispose();
                batchedChange = null;
            }
        }

        // The following method handles the slider control's 
        // ValueChanged event. It sets the value of the 
        // Background opacity by using the ModelProperty type.
        void slider_ValueChanged(
            object sender, 
            RoutedPropertyChangedEventArgs<double> e)
        {
            double newOpacityValue = e.NewValue;

            // During setup, don't make a value local and set the opacity.
            if (newOpacityValue == GetCurrentOpacity())
            {
                return;
            }

            // Access the adorned control's Background property
            // by using the ModelProperty type.
            ModelProperty backgroundProperty = 
                adornedControlModel.Properties["Background"];
            if (!backgroundProperty.IsSet)
            {
                // If the value isn't local, make it local 
                // before setting a sub-property value.
                backgroundProperty.SetValue(backgroundProperty.ComputedValue);
            }

            // Set the Opacity property on the Background Brush.
            backgroundProperty.Value.Properties["Opacity"].SetValue(newOpacityValue);
        }

        // This utility method gets the adorned control's
        // Background brush by using the ModelItem.
        private double GetCurrentOpacity()
        {
            Brush backgroundBrushComputedValue =
                (Brush)adornedControlModel.Properties["Background"].ComputedValue;

            return backgroundBrushComputedValue.Opacity;
        }
    }
}

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.Interaction Namespace

Other Resources

Adorner Architecture

Feature Providers and Feature Connectors

Walkthrough: Creating a Design-time Adorner