演练：创建菜单提供程序

项目
05/28/2012

[本文档仅供预览，在以后的发行版中可能会发生更改。包含的空白主题用作占位符。]

本演练演示如何创建 windows presentation foundation 自定义控件的一个设计 (WPF)时菜单提供程序。可以使用此快捷菜单项设置 Background 属性的值在自定义按钮控件上。有关完整的代码清单，请参见从站点的上下文菜单提供程序示例。 WPF 设计器扩展性示例

在本演练中，您将执行下列任务:

创建一个 WPF 自定义控件库项目。
创建设计时元数据的一个单独的程序集。
实现菜单提供程序。
使用控件在设计时。

完成后，您将知道如何创建自定义控件的菜单提供程序。

备注

您看到的对话框和菜单命令可能会与 " 帮助 " 中的描述不同具体取决于您现用的设置或版本。若要更改设置，请选择在工具菜单的 导入和导出设置 。有关更多信息，请参见 Visual Studio 设置。

系统必备

您需要以下组件来完成本演练:

Visual Studio 2012 RC.

创建自定义控件

第一步是为自定义控件创建项目。该控件是带有少量设计时代码的一个简单的按钮，使用 GetIsInDesignMode 方法实现设计时行为。

创建自定义控件

创建新 WPF 自定义控件库名为 CustomControlLibrary的项目在 Visual Basic 或 Visual C#。

CustomControl1 的代码在代码编辑器中打开。
在 解决方案资源管理器，将代码文件的名称更改为 ButtonWithDesignTime.cs 或 ButtonWithDesignTime.vb。如果此项目请求的出现消息框是要执行重命名所有引用，单击是。
打开 ButtonWithDesignTime.cs 或 ButtonWithDesignTime.vb 在代码编辑器中。

用下面的代码替换自动生成的代码。，当按钮出现在设计器中时，此代码从 Button 继承并显示文本 “已激活设计模式”。

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

Public Class ButtonWithDesignTime
    Inherits Button

    Public Sub New()
        ' The GetIsInDesignMode check and the following design-time 
        ' code are optional and shown only for demonstration.
        If DesignerProperties.GetIsInDesignMode(Me) Then
            Content = "Design mode active"
        End If

    End Sub
End Class

using System;
using System.Collections.Generic;
using System.Text;
using System.Windows.Controls;
using System.Windows.Media;
using System.ComponentModel;

namespace CustomControlLibrary
{
    public class ButtonWithDesignTime : Button
    {
        public ButtonWithDesignTime()
        {
            // The GetIsInDesignMode check and the following design-time 
            // code are optional and shown only for demonstration.
            if (DesignerProperties.GetIsInDesignMode(this))
            {
                Content = "Design mode active";
            }
        }
    }
}

将项目的输出路径设置为 “bin \”。
生成解决方案。

创建设计时元数据程序集

设计时代码在特定元数据程序集中部署。对于本演练，上下文菜单实现在一个名为 CustomControlLibrary.VisualStudio.Design 的程序集中部署。有关更多信息，请参见提供设计时元数据。

创建设计时元数据程序集

在 Visual Basic 中添加个新的类库名为 CustomControlLibrary.VisualStudio.Design 的项目或 Visual c# 为解决方案。
将项目的输出路径设置为 “ \ CustomControlLibrary \ bin \”。这在同一文件夹使控件的程序集和元数据程序集，使设计器的元数据发现。
添加对下列 WPF 程序集。
- PresentationCore
- PresentationFramework
- System.Xaml
- WindowsBase
添加对以下 WPF Designer 程序集。
- Microsoft.Windows.Design.Extensibility
- Microsoft.Windows.Design.Interaction
添加对 CustomControlLibrary 项目。
在 解决方案资源管理器，将 Class1 代码文件的名称改为 Metadata.cs 或 Metadata.vb。如果此项目请求的出现消息框是要执行重命名所有引用，单击是。

用下面的代码替换自动生成的代码。将自定义设计时实现附加到 ButtonWithDesignTime 类的此代码创建 AttributeTable 。

Imports System
Imports System.Collections.Generic
Imports System.Text
Imports System.ComponentModel
Imports System.Windows.Media
Imports System.Windows.Controls
Imports System.Windows
Imports CustomControlLibrary
Imports Microsoft.Windows.Design.Features
Imports Microsoft.Windows.Design.Metadata
'Imports CustomControlLibrary.VisualStudio.Design.Slid

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

            ' Add the menu provider to the design-time metadata.
            builder.AddCustomAttributes(GetType(ButtonWithDesignTime), _
                                        New FeatureAttribute(GetType(CustomContextMenuProvider)))

            Return builder.CreateTable()
        End Get
    End Property
End Class

using System;
using System.Collections.Generic;
using System.Text;
using System.ComponentModel;
using System.Windows.Media;
using System.Windows.Controls;
using System.Windows;

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

// The ProvideMetadata assembly-level attribute indicates to designers
// that this assembly contains a class that provides an attribute table. 
[assembly: ProvideMetadata(typeof(CustomControlLibrary.VisualStudio.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 IProvideAttributeTable. If found, designers instantiate 
    // this class and access its AttributeTable property automatically.
    internal class Metadata : IProvideAttributeTable
    {
        // Accessed by the designer to register any design-time metadata.
        public AttributeTable AttributeTable
        {
            get
            {
                AttributeTableBuilder builder = new AttributeTableBuilder();

                // Add the menu provider to the design-time metadata.
                builder.AddCustomAttributes(
                    typeof(ButtonWithDesignTime),
                    new FeatureAttribute(typeof(CustomContextMenuProvider)));

                return builder.CreateTable(); 
            }
        }
    }
}

保存解决方案。

实现菜单提供程序

菜单提供程序在名为 CustomContextMenuProvider的类型中实现的。提供的 MenuAction 启用设置控件的 Background 属性在设计时。

实现菜单提供程序

将名为 CustomContextMenuProvider 的新类添加到 CustomControlLibrary.VisualStudio.Design 项目。

在 CustomContextMenuProvider的代码编辑器中，用以下代码替换自动生成的代码。提供自定义 MenuAction的此代码实现 PrimarySelectionContextMenuProvider 。

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);
        }
    }
}

生成解决方案。

测试设计时实现

代码，就象使用任何其他 WPF 控件，可以使用 ButtonWithDesignTime 控件。 WPF Designer 处理所有设计时对象的创建。

测试设计时实现

添加在 Visual Basic 中的新 WPF 名为 DemoApplication 的应用程序项目或 Visual c# 为解决方案。

在 MainWindow.xaml WPF Designer打开。
添加对 CustomControlLibrary 项目。

在 XAML 视图中，用以下 XAML 替换自动生成的 XAML。此 XAML 将添加对 CustomControlLibrary 命名空间并添加 ButtonWithDesignTime 自定义控件。该按钮出现在且带有文本 “已激活设计模式”设计 " 视图中，表明该按钮处于设计模式下。如果该按钮未出现，可能需要单击设计器顶部的信息栏以重新加载视图。

<Window x:Class="DemoApplication.MainWindow"
    xmlns="https://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="https://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:cc="clr-namespace:CustomControlLibrary;assembly=CustomControlLibrary"
    Title="Window1" Height="300" Width="300">
    <Grid>
        <cc:ButtonWithDesignTime Margin="30,30,30,30" Background="#FFD4D0C8"></cc:ButtonWithDesignTime>
    </Grid>
</Window>

在设计视图中，单击 ButtonWithDesignTime 选择控件。
右击 ButtonWithDesignTime 控件，指向 设置背景，然后选择蓝色。

控件的背景设置为蓝色。在 XAML 视图中， Background 属性设置为菜单操作指定的值。
运行 DemoApplication 项目。

在运行时，该按钮具有背景将使用快捷菜单。

后续步骤

可以添加更多的自定义设计时功能。您的自定义控件。

添加自定义装饰器添加到控件的设计时。有关更多信息，请参见演练：创建设计时装饰器。
创建自定义类型的一个编辑器，可在 " 属性 " 窗口中使用。有关更多信息，请参见如何：创建值编辑器。

请参见

参考

PrimarySelectionContextMenuProvider

其他资源

高级扩展性概念

WPF 设计器扩展性

WPF 设计器扩展性示例

通过

演练：创建菜单提供程序

系统必备

创建自定义控件

创建自定义控件

创建设计时元数据程序集

创建设计时元数据程序集

实现菜单提供程序

实现菜单提供程序

测试设计时实现

测试设计时实现

后续步骤

请参见

参考

其他资源

其他资源