class/System/System.ComponentModel/TypeDescriptionProvider.cs

   1 //
   2 // System.ComponentModel.TypeDescriptionProvider
   3 //
   4 // Authors:
   5 //              Ivan N. Zlatev (contact i-nZ.net)
   6 //
   7 // (C) 2007 Ivan N. Zlatev
   8
   9 //
  10 // Permission is hereby granted, free of charge, to any person obtaining
  11 // a copy of this software and associated documentation files (the
  12 // "Software"), to deal in the Software without restriction, including
  13 // without limitation the rights to use, copy, modify, merge, publish,
  14 // distribute, sublicense, and/or sell copies of the Software, and to
  15 // permit persons to whom the Software is furnished to do so, subject to
  16 // the following conditions:
  17 //
  18 // The above copyright notice and this permission notice shall be
  19 // included in all copies or substantial portions of the Software.
  20 //
  21 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  22 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  23 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  24 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  25 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  26 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  27 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  28 //
  29
  30 #if NET_2_0
  31
  32 using System;
  33 using System.Collections;
  34
  35 namespace System.ComponentModel
  36 {
  37
  38         public abstract class TypeDescriptionProvider
  39         {
  40
  41                 private sealed class EmptyCustomTypeDescriptor : CustomTypeDescriptor
  42                 {
  43                 }
  44
  45                 private EmptyCustomTypeDescriptor _emptyCustomTypeDescriptor;
  46                 private TypeDescriptionProvider _parent;
  47
  48                 protected TypeDescriptionProvider ()
  49                 {
  50                 }
  51
  52                 protected TypeDescriptionProvider (TypeDescriptionProvider parent)
  53                 {
  54                         _parent = parent;
  55                 }
  56
  57                 public virtual object CreateInstance (IServiceProvider provider, Type objectType, Type[] argTypes, object[] args)
  58                 {
  59                         if (_parent != null)
  60                                 return _parent.CreateInstance (provider, objectType, argTypes, args);
  61
  62                         return System.Activator.CreateInstance (objectType, args);
  63                 }
  64
  65
  66                 public virtual IDictionary GetCache (object instance)
  67                 {
  68                         if (_parent != null)
  69                                 return _parent.GetCache (instance);
  70
  71                         return null;
  72                 }
  73
  74
  75                 public virtual ICustomTypeDescriptor GetExtendedTypeDescriptor (object instance)
  76                 {
  77                         if (_parent != null)
  78                                 return _parent.GetExtendedTypeDescriptor (instance);
  79
  80                         if (_emptyCustomTypeDescriptor == null)
  81                                 _emptyCustomTypeDescriptor = new EmptyCustomTypeDescriptor ();
  82
  83                         return _emptyCustomTypeDescriptor;
  84                 }
  85
  86
  87                 public virtual string GetFullComponentName (object component)
  88                 {
  89                         if (_parent != null)
  90                                 return _parent.GetFullComponentName (component);
  91
  92                         return GetTypeDescriptor (component).GetComponentName ();
  93                 }
  94
  95
  96                 public Type GetReflectionType (object instance)
  97                 {
  98                         if (instance == null)
  99                                 throw new ArgumentNullException ("instance");
 100
 101                         return GetReflectionType (instance.GetType (), instance);
 102                 }
 103
 104
 105                 public Type GetReflectionType (Type objectType)
 106                 {
 107                         return GetReflectionType (objectType, null);
 108                 }
 109
 110
 111                 public virtual Type GetReflectionType (Type objectType, object instance)
 112                 {
 113                         if (_parent != null)
 114                                 return _parent.GetReflectionType (objectType, instance);
 115
 116                         return objectType;
 117                 }
 118
 119
 120                 public ICustomTypeDescriptor GetTypeDescriptor (object instance)
 121                 {
 122                         if (instance == null)
 123                                 throw new ArgumentNullException ("instance");
 124
 125                         return GetTypeDescriptor (instance.GetType (), instance);
 126                 }
 127
 128
 129                 public ICustomTypeDescriptor GetTypeDescriptor (Type objectType)
 130                 {
 131                         return GetTypeDescriptor (objectType, null);
 132                 }
 133
 134
 135                 public virtual ICustomTypeDescriptor GetTypeDescriptor (Type objectType, object instance)
 136                 {
 137                         if (_parent != null)
 138                                 return _parent.GetTypeDescriptor (objectType, instance);
 139
 140                         if (_emptyCustomTypeDescriptor == null)
 141                                 _emptyCustomTypeDescriptor = new EmptyCustomTypeDescriptor ();
 142
 143                         return _emptyCustomTypeDescriptor;
 144                 }
 145
 146         }
 147
 148 }
 149
 150 #endif