AdornerProvider.Activate 메서드

아티클
08/10/2011

디자이너에서 표시기를 처음 요청할 때 호출됩니다.

네임스페이스: Microsoft.Windows.Design.Interaction
어셈블리: Microsoft.Windows.Design.Interaction(Microsoft.Windows.Design.Interaction.dll)

구문

‘선언
Protected Overridable Sub Activate ( _
    item As ModelItem _
)

protected virtual void Activate(
    ModelItem item
)

protected:
virtual void Activate(
    ModelItem^ item
)

abstract Activate : 
        item:ModelItem -> unit 
override Activate : 
        item:ModelItem -> unit

protected function Activate(
    item : ModelItem
)

매개 변수

item
형식: Microsoft.Windows.Design.Model.ModelItem
표시된 요소를 나타내는 ModelItem입니다.

설명

표시기 공급자는 표시된 요소 항목 또는 뷰를 사용하여 표시기를 초기화할 수 있습니다. 이러한 컨텍스트가 필요하지 않은 경우 표시기 공급자는 Activate 메서드를 오버로드하지 않고 생성자에서 표시기를 만들 수 있습니다. 이 메서드는 표시기가 디자이너 UI의 부모로 지정되기 전에 호출됩니다.

AdornerProvider 인스턴스를 해당 수명 동안 여러 번 활성화하고 비활성화해야 할 수도 있습니다. 이를 고려하여 Activate 및 Deactivate 메서드를 구현합니다.

예제

다음 코드 예제에서는 Activate 메서드를 재정의하여 디자인 타임에 표시된 컨트롤의 Background 속성을 설정하는 데 사용되는 AdornerPanel을 만들어 Slider 컨트롤을 호스팅하는 방법을 보여 줍니다. 자세한 내용은 연습: 디자인 타임 표시기 만들기을 참조하십시오.

        ' 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 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;
            } 
        }