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
  36 namespace System.ComponentModel {
  37
  38         [DesignerCategory ("Component")]
  39         public class Component : MarshalByRefObject, IComponent, IDisposable
  40         {
  41
  42                 private EventHandlerList event_handlers;
  43                 private ISite mySite;
  44                 private object disposedEvent = new object ();
  45
  46                 public Component ()
  47                 {
  48                         event_handlers = null;
  49                 }
  50
  51                 [Browsable (false), DesignerSerializationVisibility (DesignerSerializationVisibility.Hidden)]
  52                 public IContainer Container {
  53                         get {
  54                                 if (mySite == null)
  55                                         return null;
  56                                 return mySite.Container;
  57                         }
  58                 }
  59
  60                 [Browsable (false), DesignerSerializationVisibility (DesignerSerializationVisibility.Hidden)]
  61                 protected bool DesignMode {
  62                         get {
  63                                 if (mySite == null)
  64                                         return false;
  65                                 return mySite.DesignMode;
  66                         }
  67                 }
  68
  69                 protected EventHandlerList Events {
  70                         get {
  71                                 // Note: space vs. time tradeoff
  72                                 // We create the object here if it's never be accessed before.  This potentially
  73                                 // saves space. However, we must check each time the propery is accessed to
  74                                 // determine whether we need to create the object, which increases overhead.
  75                                 // We could put the creation in the contructor, but that would waste space
  76                                 // if it were never used.  However, accessing this property would be faster.
  77                                 if (null == event_handlers)
  78                                         event_handlers = new EventHandlerList();
  79
  80                                 return event_handlers;
  81                         }
  82                 }
  83
  84                 [Browsable (false), DesignerSerializationVisibility (DesignerSerializationVisibility.Hidden)]
  85                 public virtual ISite Site {
  86                         get { return mySite; }
  87                         set { mySite = value; }
  88                 }
  89
  90                 ~Component()
  91                 {
  92                         Dispose (false);
  93                 }
  94
  95                 public void Dispose ()
  96                 {
  97                         Dispose (true);
  98                         GC.SuppressFinalize (this);
  99                 }
 100
 101                 // <summary>
 102                 //   Controls disposal of resources used by this.
 103                 // </summary>
 104                 //
 105                 // <param name="release_all"> Controls which resources are released</param>
 106                 //
 107                 // <remarks>
 108                 //   if release_all is set to true, both managed and unmanaged
 109                 //   resources should be released.  If release_all is set to false,
 110                 //   only unmanaged resources should be disposed
 111                 // </remarks>
 112                 protected virtual void Dispose (bool release_all)
 113                 {
 114                         if (release_all) {
 115                                 EventHandler eh = (EventHandler) Events [disposedEvent];
 116                                 if (eh != null)
 117                                         eh (this, EventArgs.Empty);
 118                         }
 119                         mySite = null;
 120                 }
 121
 122                 protected virtual object GetService (Type service)
 123                 {
 124                         if (mySite != null) {
 125                                 return mySite.GetService(service);
 126                         }
 127                         return null;
 128                 }
 129
 130                 public override string ToString ()
 131                 {
 132                         if (mySite == null)
 133                                 return GetType ().ToString ();
 134                         return String.Format ("{0} [{1}]", mySite.Name, GetType ().ToString ());
 135                 }
 136
 137                 [Browsable (false), EditorBrowsable (EditorBrowsableState.Advanced)]
 138                 public event EventHandler Disposed {
 139                         add { Events.AddHandler (disposedEvent, value); }
 140                         remove { Events.RemoveHandler (disposedEvent, value); }
 141                 }
 142         }
 143
 144 }