C# IComponentChangeService接口代碼示例

//引入命名空間
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 );
    }
    }
}