ContextMenuProvider – třída

Článek
08/11/2011

Definuje sadu položek nabídky, které jsou zobrazeny v místní nabídce.

Hierarchie dědičnosti

System.Object
  Microsoft.Windows.Design.Features.FeatureProvider
    Microsoft.Windows.Design.Interaction.ContextMenuProvider
      Microsoft.Windows.Design.Interaction.PrimarySelectionContextMenuProvider

Obor názvů: Microsoft.Windows.Design.Interaction
Sestavení: Microsoft.Windows.Design.Interaction (v Microsoft.Windows.Design.Interaction.dll)

Syntaxe

'Deklarace
Public MustInherit Class ContextMenuProvider _
    Inherits FeatureProvider

public abstract class ContextMenuProvider : FeatureProvider

public ref class ContextMenuProvider abstract : public FeatureProvider

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

public abstract class ContextMenuProvider extends FeatureProvider

Typ ContextMenuProvider zveřejňuje následující členy.

Konstruktory

	Název	Popis
	ContextMenuProvider	Inicializuje novou instanci ContextMenuProvider Třída

Na začátek

Vlastnosti

	Název	Popis
	Items	Načte položky přidat do kontextové nabídky.

Na začátek

Metody

	Název	Popis
	Equals	Určuje, zda zadaná Object se rovná aktuální Object. (Zděděno z Object.)
	Finalize	Umožňuje zkuste uvolnit prostředky a provádět další operace vyčištění před je převzaty systémem pro uvolnění objektu. (Zděděno z Object.)
	GetHashCode	Slouží jako funkce hash určitého typu. (Zděděno z Object.)
	GetType	Získává Type aktuální instance. (Zděděno z Object.)
	MemberwiseClone	Vytvoří kopii aktuální Object. (Zděděno z Object.)
	ToString	Vrátí řetězec, který představuje aktuální objekt. (Zděděno z Object.)
	Update	Zvýší UpdateItemStatus událostí, takže lze obnovovat viditelnost a povolen stav položek nabídek.

Na začátek

Události

	Název	Popis
	UpdateItemStatus	Dojde k položce nabídky má být zobrazen.

Na začátek

Poznámky

Dědí ContextMenuProvider třídy, pokud chcete přidat položku nabídky kontextové nabídky určitému kontextu. Použitím zásad, například PrimarySelectionPolicy a SelectionParentPolicy, můžete řídit při vytvoření kontextové nabídky zprostředkovatele.

Existence ContextMenuProvider je dočasné. Není Předpokládejme, že bude trvalé dlouhou dobu.

Příklady

Následující příklad kódu ukazuje, jak lze odvodit z vlastní typ PrimarySelectionContextMenuProvider Třída Odvozený typ implementuje vlastní kontextovou nabídku, která se nastavuje Background Vlastnosti ovládacího prvku v čase návrhu. Další informace naleznete v tématu Walkthrough: Creating a MenuAction.

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

' The CustomContextMenuProvider class provides two context menu items
' at design time. These are implemented with the MenuAction class.
Class CustomContextMenuProvider
    Inherits PrimarySelectionContextMenuProvider

    Private setBackgroundToBlueMenuAction As MenuAction
    Private clearBackgroundMenuAction As MenuAction

    ' The provider's constructor sets up the MenuAction objects 
    ' and the the MenuGroup which holds them.
    Public Sub New()

        ' Set up the MenuAction which sets the control's 
        ' background to Blue.
        setBackgroundToBlueMenuAction = New MenuAction("Blue")
        setBackgroundToBlueMenuAction.Checkable = True
        AddHandler setBackgroundToBlueMenuAction.Execute, AddressOf SetBackgroundToBlue_Execute

        ' Set up the MenuAction which sets the control's 
        ' background to its default value.
        clearBackgroundMenuAction = New MenuAction("Cleared")
        clearBackgroundMenuAction.Checkable = True
        AddHandler clearBackgroundMenuAction.Execute, AddressOf ClearBackground_Execute

        ' Set up the MenuGroup which holds the MenuAction items.
        Dim backgroundFlyoutGroup As New MenuGroup("SetBackgroundsGroup", "Set Background")

        ' If HasDropDown is false, the group appears inline, 
        ' instead of as a flyout. Set to true.
        backgroundFlyoutGroup.HasDropDown = True
        backgroundFlyoutGroup.Items.Add(setBackgroundToBlueMenuAction)
        backgroundFlyoutGroup.Items.Add(clearBackgroundMenuAction)
        Me.Items.Add(backgroundFlyoutGroup)

        ' The UpdateItemStatus event is raised immediately before 
        ' this provider shows its tabs, which provides the opportunity 
        ' to set states.
        AddHandler UpdateItemStatus, AddressOf CustomContextMenuProvider_UpdateItemStatus

    End Sub

    ' The following method handles the UpdateItemStatus event.
    ' It sets the MenuAction states according to the state
    ' of the control's Background property. This method is
    ' called before the context menu is shown.
    Sub CustomContextMenuProvider_UpdateItemStatus( _
        ByVal sender As Object, _
        ByVal e As MenuActionEventArgs)

        ' Turn everything on, and then based on the value 
        ' of the BackgroundProperty, selectively turn some off.
        clearBackgroundMenuAction.Checked = False
        clearBackgroundMenuAction.Enabled = True
        setBackgroundToBlueMenuAction.Checked = False
        setBackgroundToBlueMenuAction.Enabled = True

        ' Get a ModelItem which represents the selected control. 
        Dim selectedControl As ModelItem = _
            e.Selection.PrimarySelection

        ' Get the value of the Background property from the ModelItem.
        Dim backgroundProperty As ModelProperty = _
            selectedControl.Properties("Background")

        ' Set the MenuAction items appropriately.
        If Not backgroundProperty.IsSet Then
            clearBackgroundMenuAction.Checked = True
            clearBackgroundMenuAction.Enabled = False
        ElseIf backgroundProperty.ComputedValue.Equals(Brushes.Blue) Then
            setBackgroundToBlueMenuAction.Checked = True
            setBackgroundToBlueMenuAction.Enabled = False
        End If

    End Sub

    ' The following method handles the Execute event. 
    ' It sets the Background property to its default value.
    Sub ClearBackground_Execute( _
        ByVal sender As Object, _
        ByVal e As MenuActionEventArgs)

        Dim selectedControl As ModelItem = e.Selection.PrimarySelection
        selectedControl.Properties("Background").ClearValue()

    End Sub

    ' The following method handles the Execute event. 
    ' It sets the Background property to Brushes.Blue.
    Sub SetBackgroundToBlue_Execute( _
        ByVal sender As Object, _
        ByVal e As MenuActionEventArgs)

        Dim selectedControl As ModelItem = e.Selection.PrimarySelection
        selectedControl.Properties("Background").SetValue(Brushes.Blue)

    End Sub

End Class

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

namespace CustomControlLibrary.VisualStudio.Design
{
    // The CustomContextMenuProvider class provides two context menu items
    // at design time. These are implemented with the MenuAction class.
    class CustomContextMenuProvider : PrimarySelectionContextMenuProvider
    {
        private MenuAction setBackgroundToBlueMenuAction;
        private MenuAction clearBackgroundMenuAction;

        // The provider's constructor sets up the MenuAction objects 
        // and the the MenuGroup which holds them.
        public CustomContextMenuProvider()
        {   
            // Set up the MenuAction which sets the control's 
            // background to Blue.
            setBackgroundToBlueMenuAction = new MenuAction("Blue");
            setBackgroundToBlueMenuAction.Checkable = true;
            setBackgroundToBlueMenuAction.Execute += 
                new EventHandler<MenuActionEventArgs>(SetBackgroundToBlue_Execute);

            // Set up the MenuAction which sets the control's 
            // background to its default value.
            clearBackgroundMenuAction = new MenuAction("Cleared");
            clearBackgroundMenuAction.Checkable = true;
            clearBackgroundMenuAction.Execute += 
                new EventHandler<MenuActionEventArgs>(ClearBackground_Execute);

            // Set up the MenuGroup which holds the MenuAction items.
            MenuGroup backgroundFlyoutGroup = 
                new MenuGroup("SetBackgroundsGroup", "Set Background");

            // If HasDropDown is false, the group appears inline, 
            // instead of as a flyout. Set to true.
            backgroundFlyoutGroup.HasDropDown = true;
            backgroundFlyoutGroup.Items.Add(setBackgroundToBlueMenuAction);
            backgroundFlyoutGroup.Items.Add(clearBackgroundMenuAction);
            this.Items.Add(backgroundFlyoutGroup);

            // The UpdateItemStatus event is raised immediately before 
            // this provider shows its tabs, which provides the opportunity 
            // to set states.
            UpdateItemStatus += 
                new EventHandler<MenuActionEventArgs>(
                    CustomContextMenuProvider_UpdateItemStatus);
        }

        // The following method handles the UpdateItemStatus event.
        // It sets the MenuAction states according to the state
        // of the control's Background property. This method is
        // called before the context menu is shown.
        void CustomContextMenuProvider_UpdateItemStatus(
            object sender, 
            MenuActionEventArgs e)
        {
            // Turn everything on, and then based on the value 
            // of the BackgroundProperty, selectively turn some off.
            clearBackgroundMenuAction.Checked = false;
            clearBackgroundMenuAction.Enabled = true;
            setBackgroundToBlueMenuAction.Checked = false;
            setBackgroundToBlueMenuAction.Enabled = true;

            // Get a ModelItem which represents the selected control. 
            ModelItem selectedControl = e.Selection.PrimarySelection;

            // Get the value of the Background property from the ModelItem.
            ModelProperty backgroundProperty = 
                selectedControl.Properties["Background"];

            // Set the MenuAction items appropriately.
            if (!backgroundProperty.IsSet)
            {
                clearBackgroundMenuAction.Checked = true;
                clearBackgroundMenuAction.Enabled = false;
            }
            else if (backgroundProperty.ComputedValue == Brushes.Blue)
            {
                setBackgroundToBlueMenuAction.Checked = true;
                setBackgroundToBlueMenuAction.Enabled = false;
            }
        }

        // The following method handles the Execute event. 
        // It sets the Background property to its default value.
        void ClearBackground_Execute(
            object sender, 
            MenuActionEventArgs e)
        {
            ModelItem selectedControl = e.Selection.PrimarySelection;
            selectedControl.Properties["Background"].ClearValue();
        }

        // The following method handles the Execute event. 
        // It sets the Background property to Brushes.Blue.
        void SetBackgroundToBlue_Execute(
            object sender, 
            MenuActionEventArgs e)
        {
            ModelItem selectedControl = e.Selection.PrimarySelection;
            selectedControl.Properties["Background"].SetValue(Brushes.Blue);
        }
    }
}

Zabezpečení podprocesu

Všechny veřejné členy static (Shared v jazyce Visual Basic) tohoto typu jsou zabezpečeny pro používání podprocesů. Zabezpečení sdílených členů pro používání podprocesů není zaručeno.