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

   1 //
   2 // System.ComponentModel.Component.cs
   3 //
   4 // Author:
   5 //  Miguel de Icaza (miguel@ximian.com)
   6 //  Andreas Nahr (ClassDevelopment@A-SoftTech.com)
   7 //
   8 // (C) Ximian, Inc.  http://www.ximian.com
   9 // (C) 2003 Andreas Nahr
  10 //
  11
  12 //
  13 // Permission is hereby granted, free of charge, to any person obtaining
  14 // a copy of this software and associated documentation files (the
  15 // "Software"), to deal in the Software without restriction, including
  16 // without limitation the rights to use, copy, modify, merge, publish,
  17 // distribute, sublicense, and/or sell copies of the Software, and to
  18 // permit persons to whom the Software is furnished to do so, subject to
  19 // the following conditions:
  20 //
  21 // The above copyright notice and this permission notice shall be
  22 // included in all copies or substantial portions of the Software.
  23 //
  24 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  25 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  26 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  27 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  28 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  29 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  30 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  31 //
  32
  33 using System;
  34 using System.ComponentModel;
  35 using System.Runtime.InteropServices;
  36
  37 namespace System.ComponentModel {
  38
  39         [DesignerCategory ("Component")]
  40 #if NET_2_0
  41         [ComVisible (true)]
  42         [ClassInterface (ClassInterfaceType.AutoDispatch)]
  43 #endif
  44         public class Component : MarshalByRefObject, IComponent, IDisposable
  45         {
  46
  47                 private EventHandlerList event_handlers;
  48                 private ISite mySite;
  49                 private object disposedEvent = new object ();
  50
  51                 public Component ()
  52                 {
  53                         event_handlers = null;
  54                 }
  55
  56 #if NET_2_0
  57                 protected virtual bool CanRaiseEvents {
  58                         get { return false; }
  59                 }
  60 #endif
  61
  62                 [Browsable (false), DesignerSerializationVisibility (DesignerSerializationVisibility.Hidden)]
  63                 public virtual ISite Site
  64                 {
  65                         get { return mySite; }
  66                         set { mySite = value; }
  67                 }
  68
  69                 [Browsable (false), DesignerSerializationVisibility (DesignerSerializationVisibility.Hidden)]
  70                 public IContainer Container {
  71                         get {
  72                                 if (mySite == null)
  73                                         return null;
  74                                 return mySite.Container;
  75                         }
  76                 }
  77
  78                 [Browsable (false), DesignerSerializationVisibility (DesignerSerializationVisibility.Hidden)]
  79                 protected bool DesignMode {
  80                         get {
  81                                 if (mySite == null)
  82                                         return false;
  83                                 return mySite.DesignMode;
  84                         }
  85                 }
  86
  87                 protected EventHandlerList Events {
  88                         get {
  89                                 // Note: space vs. time tradeoff
  90                                 // We create the object here if it's never be accessed before.  This potentially
  91                                 // saves space. However, we must check each time the propery is accessed to
  92                                 // determine whether we need to create the object, which increases overhead.
  93                                 // We could put the creation in the contructor, but that would waste space
  94                                 // if it were never used.  However, accessing this property would be faster.
  95                                 if (null == event_handlers)
  96                                         event_handlers = new EventHandlerList();
  97
  98                                 return event_handlers;
  99                         }
 100                 }
 101
 102                 ~Component()
 103                 {
 104                         Dispose (false);
 105                 }
 106
 107 #if TARGET_JVM
 108                 public virtual void Dispose ()
 109                 {
 110                         Dispose (true);
 111                 }
 112 #else
 113                 public void Dispose ()
 114                 {
 115                         Dispose (true);
 116                         GC.SuppressFinalize (this);
 117                 }
 118 #endif
 119
 120                 // <summary>
 121                 //   Controls disposal of resources used by this.
 122                 // </summary>
 123                 //
 124                 // <param name="release_all"> Controls which resources are released</param>
 125                 //
 126                 // <remarks>
 127                 //   if release_all is set to true, both managed and unmanaged
 128                 //   resources should be released.  If release_all is set to false,
 129                 //   only unmanaged resources should be disposed
 130                 // </remarks>
 131                 protected virtual void Dispose (bool release_all)
 132                 {
 133                         if (release_all) {
 134                                 if (mySite != null && mySite.Container != null)
 135                                         mySite.Container.Remove (this);
 136                                 EventHandler eh = (EventHandler) Events [disposedEvent];
 137                                 if (eh != null)
 138                                         eh (this, EventArgs.Empty);
 139                         }
 140                 }
 141
 142                 protected virtual object GetService (Type service)
 143                 {
 144                         if (mySite != null) {
 145                                 return mySite.GetService(service);
 146                         }
 147                         return null;
 148                 }
 149
 150                 public override string ToString ()
 151                 {
 152                         if (mySite == null)
 153                                 return GetType ().ToString ();
 154                         return String.Format ("{0} [{1}]", mySite.Name, GetType ().ToString ());
 155                 }
 156
 157                 [Browsable (false), EditorBrowsable (EditorBrowsableState.Advanced)]
 158                 public event EventHandler Disposed {
 159                         add { Events.AddHandler (disposedEvent, value); }
 160                         remove { Events.RemoveHandler (disposedEvent, value); }
 161                 }
 162         }
 163
 164 }