mono/mcs/class/System/System.ComponentModel/Component.cs

//
// System.ComponentModel.Component.cs
//
// Author:
//   Miguel de Icaza ([email protected])
//
// (C) Ximian, Inc.  http://www.ximian.com
//

using System;

namespace System.ComponentModel {

	// <summary>
	//   Component class.
	// </summary>
	//
	// <remarks>
	//   Longer description
	// </remarks>
	public class Component : MarshalByRefObject, IComponent, IDisposable {

		EventHandlerList event_handlers;
		ISite            mySite;
		object disposedEvent = new object ();

		// <summary>
		//   Component Constructor
		// </summary>
		public Component ()
		{
			event_handlers = null;
		}

		// <summary>
		//   Get IContainer of this Component
		// </summary>
		public IContainer Container {
			get {
				return mySite.Container;
			}
		}

		protected bool DesignMode {
			get {
				return mySite.DesignMode;
			}
		}

		protected EventHandlerList Events {
			get {
				// Note: space vs. time tradeoff
				// We create the object here if it's never be accessed before.  This potentially 
				// saves space. However, we must check each time the propery is accessed to
				// determine whether we need to create the object, which increases overhead.
				// We could put the creation in the contructor, but that would waste space
				// if it were never used.  However, accessing this property would be faster.
				if (null == event_handlers)
				{
					event_handlers = new EventHandlerList();
				}
				return event_handlers;
			}
		}

		public virtual ISite Site {
			get {
				return mySite;
			}

			set {
				mySite = value;
			}
		}

		~Component()
		{
			Dispose (false);
		}

		// <summary>
		//   Dispose resources used by this component
		// </summary>
		public void Dispose ()
		{
			Dispose (true);
			GC.SuppressFinalize (this);
		}

		// <summary>
		//   Controls disposal of resources used by this.
		// </summary>
		//
		// <param name="release_all"> Controls which resources are released</param>
		//
		// <remarks>
		//   if release_all is set to true, both managed and unmanaged
		//   resources should be released.  If release_all is set to false,
		//   only unmanaged resources should be disposed
		// </remarks>
		protected virtual void Dispose (bool release_all)
		{
			if (release_all) {
				EventHandler eh = (EventHandler) Events [disposedEvent];
				if (eh != null)
					eh (this, EventArgs.Empty);
			}
			mySite = null;
		}

		// <summary>
		//   Implements the IServiceProvider interface
		// </summary>
		[MonoTODO]
		protected virtual object GetService (Type service)
		{
			// FIXME: Not sure what this should do.
			return null;
		}

		public override string ToString ()
		{
			if (mySite == null)
				return GetType ().ToString ();
			return String.Format ("{0} [{1}]", mySite.Name, GetType ().ToString ());
		}
		// <summary>
		//   This event is called when the component is explicitly disposed.
	        // </summary>
		public event EventHandler Disposed
		{
			add {
				Events.AddHandler (disposedEvent, value);
			}
			remove {
				Events.RemoveHandler (disposedEvent, value);
			}
		}
	}
	
}