IComponentChangeService 接口

定义

命名空间:

System.ComponentModel.Design

程序集:

System.ComponentModel.TypeConverter.dll

提供一个接口来为添加、更改、移除或重命名组件的事件添加和移除事件处理程序，并提供方法来引发 ComponentChanged 或 ComponentChanging 事件。

C#

public interface IComponentChangeService

示例

以下示例演示如何使用 IComponentChangeService 接口接收有关在设计模式下添加、删除和更改组件的通知。

C#

using System;
using System.Data;
using System.Drawing;
using System.Collections;
using System.ComponentModel;
using System.ComponentModel.Design;
using System.Windows.Forms;

/*  This sample illustrates how to use the IComponentChangeService interface 
    to handle component change events.  The ComponentClass control attaches 
    event handlers when it is sited in a document, and displays a message 
    when notification that a component has been added, removed, or changed
    is received from the IComponentChangeService.

    To run this sample, add the ComponentClass control to a Form and
    add, remove, or change components to see the behavior of the
    component change event handlers. */

namespace IComponentChangeServiceExample 
{
    public class ComponentClass : System.Windows.Forms.UserControl 
    {
        private System.ComponentModel.Container components = null;
    private System.Windows.Forms.ListBox listBox1;
    private IComponentChangeService m_changeService;
 
    public ComponentClass() 
    {
        InitializeComponent();
    }

    private void InitializeComponent() 
    {
        this.listBox1 = new System.Windows.Forms.ListBox();
        this.SuspendLayout();

        // listBox1.
        this.listBox1.Location = new System.Drawing.Point(24, 16);
        this.listBox1.Name = "listBox1";
        this.listBox1.Size = new System.Drawing.Size(576, 277);
        this.listBox1.TabIndex = 0;
           
        // ComponentClass.
        this.Controls.AddRange(new System.Windows.Forms.Control[] {this.listBox1});
        this.Name = "ComponentClass";
        this.Size = new System.Drawing.Size(624, 320);

            this.ResumeLayout(false);
    }

    // This override allows the control to register event handlers for IComponentChangeService events
    // at the time the control is sited, which happens only in design mode.
    public override ISite Site 
    {
        get 
        {
        return base.Site;
        }
        set 
        {		
        // Clear any component change event handlers.
        ClearChangeNotifications();		
                
        // Set the new Site value.
        base.Site = value;

        m_changeService = (IComponentChangeService)GetService(typeof(IComponentChangeService));

        // Register event handlers for component change events.
        RegisterChangeNotifications();			
        }
    }

    private void ClearChangeNotifications()
    {
        // The m_changeService value is null when not in design mode, 
        // as the IComponentChangeService is only available at design time.	
        m_changeService = (IComponentChangeService)GetService(typeof(IComponentChangeService));

        // Clear our the component change events to prepare for re-siting.				
        if (m_changeService != null) 
        {
        m_changeService.ComponentChanged -= new ComponentChangedEventHandler(OnComponentChanged);
        m_changeService.ComponentChanging -= new ComponentChangingEventHandler(OnComponentChanging);
        m_changeService.ComponentAdded -= new ComponentEventHandler(OnComponentAdded);
        m_changeService.ComponentAdding -= new ComponentEventHandler(OnComponentAdding);
        m_changeService.ComponentRemoved -= new ComponentEventHandler(OnComponentRemoved);
        m_changeService.ComponentRemoving -= new ComponentEventHandler(OnComponentRemoving);
        m_changeService.ComponentRename -= new ComponentRenameEventHandler(OnComponentRename);
        }
    }

    private void RegisterChangeNotifications()
    {
        // Register the event handlers for the IComponentChangeService events
        if (m_changeService != null) 
        {
        m_changeService.ComponentChanged += new ComponentChangedEventHandler(OnComponentChanged);
        m_changeService.ComponentChanging += new ComponentChangingEventHandler(OnComponentChanging);
        m_changeService.ComponentAdded += new ComponentEventHandler(OnComponentAdded);
        m_changeService.ComponentAdding += new ComponentEventHandler(OnComponentAdding);
        m_changeService.ComponentRemoved += new ComponentEventHandler(OnComponentRemoved);
        m_changeService.ComponentRemoving += new ComponentEventHandler(OnComponentRemoving);
        m_changeService.ComponentRename += new ComponentRenameEventHandler(OnComponentRename);
        }
    }

    /* This method handles the OnComponentChanged event to display a notification. */
    private void OnComponentChanged(object sender, ComponentChangedEventArgs ce) 
    {
        if( ce.Component != null && ((IComponent)ce.Component).Site != null && ce.Member != null ) 
        OnUserChange("The " + ce.Member.Name + " member of the " + ((IComponent)ce.Component).Site.Name + " component has been changed.");
    }

    /* This method handles the OnComponentChanging event to display a notification. */
    private void OnComponentChanging(object sender, ComponentChangingEventArgs ce) 
    {
        if( ce.Component != null && ((IComponent)ce.Component).Site != null && ce.Member != null ) 
        OnUserChange("The " + ce.Member.Name + " member of the " + ((IComponent)ce.Component).Site.Name + " component is being changed.");
    }

    /* This method handles the OnComponentAdded event to display a notification. */
    private void OnComponentAdded(object sender, ComponentEventArgs ce) 
    {			
        OnUserChange("A component, " + ce.Component.Site.Name + ", has been added.");
    }

    /* This method handles the OnComponentAdding event to display a notification. */		
    private void OnComponentAdding(object sender, ComponentEventArgs ce) 
    {			
        OnUserChange("A component of type " + ce.Component.GetType().FullName + " is being added.");
    }

    /* This method handles the OnComponentRemoved event to display a notification. */
    private void OnComponentRemoved(object sender, ComponentEventArgs ce) 
    {
        OnUserChange("A component, " + ce.Component.Site.Name + ", has been removed.");
    }

    /* This method handles the OnComponentRemoving event to display a notification. */
    private void OnComponentRemoving(object sender, ComponentEventArgs ce) 
    {
        OnUserChange("A component, " + ce.Component.Site.Name + ", is being removed.");
    }

    /* This method handles the OnComponentRename event to display a notification. */
    private void OnComponentRename(object sender, ComponentRenameEventArgs ce) 
    {
        OnUserChange("A component, " + ce.OldName + ", was renamed to " + ce.NewName +".");
    }

    // This method adds a specified notification message to the control's listbox.
    private void OnUserChange(string text) 
    {
        listBox1.Items.Add(text);
    }

    // Clean up any resources being used.
    protected override void Dispose( bool disposing ) 
    {
        if( disposing ) 
        {
        ClearChangeNotifications();
            
        if(components != null) 
        {
            components.Dispose();
        }
        }
        base.Dispose( disposing );
    }
    }
}

注解

IComponentChangeService 提供了一个接口，该接口可用于指示处理以下事件的方法：

• ComponentAdded，在添加组件时引发。

• ComponentAdding，在即将添加组件时引发。

• ComponentChanged，在组件更改时引发。

• ComponentChanging，在组件即将更改时引发。

• ComponentRemoved，在移除组件时引发。

• ComponentRemoving，在组件即将移除时引发。

• ComponentRename，在重命名组件时引发。

通常，设计环境会引发这些组件添加、更改、删除或重命名事件。 使用 DesignerTransaction 对象为影响组件的设计时操作提供撤消和重做功能时，设计器应调用此接口的方法。 有关详细信息，请参阅 的文档 DesignerTransaction。 通常，只有根设计器处理这些更改通知。

此服务还提供引发组件更改事件或组件更改事件的方法。 或 PropertyDescriptor 组件可以分别使用 和 OnComponentChanging 方法指示组件已更改或正在更改OnComponentChanged。

方法

OnComponentChanged(Object, MemberDescriptor, Object, Object)	向组件更改服务通知特定组件已更改。
OnComponentChanging(Object, MemberDescriptor)	向组件更改服务通知特定组件正在发生更改。

事件

ComponentAdded	在组件已添加时发生。
ComponentAdding	在添加组件的过程中发生。
ComponentChanged	在组件已更改时发生。
ComponentChanging	在更改组件的过程中发生。
ComponentRemoved	在组件已移除时发生。
ComponentRemoving	在移除组件的过程中发生。
ComponentRename	在组件已重命名时发生。

适用于

另请参阅

• ComponentEventHandler
• ComponentChangedEventHandler
• ComponentChangingEventHandler
• ComponentRenameEventHandler
• MemberDescriptor
• DesignerTransaction