mcs/class/System/System.ComponentModel/PropertyDescriptor.cs

   1 //
   2 // System.ComponentModel.PropertyDescriptor.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.Collections;
  35 using System.Reflection;
  36 using System.Runtime.InteropServices;
  37
  38 namespace System.ComponentModel
  39 {
  40         [ComVisible (true)]
  41         public abstract class PropertyDescriptor : MemberDescriptor
  42         {
  43                 protected PropertyDescriptor (MemberDescriptor reference)
  44                 : base (reference)
  45                 {
  46                 }
  47
  48                 protected PropertyDescriptor (MemberDescriptor reference, Attribute [] attrs)
  49                 : base (reference, attrs)
  50                 {
  51                 }
  52
  53                 protected PropertyDescriptor (string name, Attribute [] attrs)
  54                 : base (name, attrs)
  55                 {
  56                 }
  57
  58                 public abstract Type ComponentType { get; }
  59
  60                 public virtual TypeConverter Converter {
  61                         get { return TypeDescriptor.GetConverter (PropertyType); }
  62                 }
  63
  64                 public virtual bool IsLocalizable {
  65                         get {
  66                                 foreach (Attribute attr in AttributeArray){
  67                                         if (attr is LocalizableAttribute)
  68                                                 return ((LocalizableAttribute) attr).IsLocalizable;
  69                                 }
  70
  71                                 return false;
  72                         }
  73                 }
  74
  75                 public abstract bool IsReadOnly { get; }
  76
  77                 public abstract Type PropertyType { get; }
  78
  79                 public DesignerSerializationVisibility SerializationVisibility {
  80                         get {
  81                                 foreach (Attribute attr in AttributeArray) {
  82                                         if (attr is DesignerSerializationVisibilityAttribute){
  83                                                 DesignerSerializationVisibilityAttribute a;
  84
  85                                                 a = (DesignerSerializationVisibilityAttribute) attr;
  86
  87                                                 return a.Visibility;
  88                                         }
  89                                 }
  90
  91                                 //
  92                                 // Is this a good default if we cant find the property?
  93                                 //
  94                                 return DesignerSerializationVisibility.Hidden;
  95                         }
  96                 }
  97
  98                 Hashtable notifiers;
  99
 100                 public virtual void AddValueChanged (object component, EventHandler handler)
 101                 {
 102                         EventHandler component_notifiers;
 103
 104                         if (component == null)
 105                                 throw new ArgumentNullException ("component");
 106
 107                         if (handler == null)
 108                                 throw new ArgumentNullException ("handler");
 109
 110                         if (notifiers == null)
 111                                 notifiers = new Hashtable ();
 112
 113                         component_notifiers = (EventHandler) notifiers [component];
 114
 115                         if (component_notifiers != null)
 116                                 component_notifiers += handler;
 117                         else
 118                                 notifiers [component] = handler;
 119                 }
 120
 121                 public virtual void RemoveValueChanged (object component, System.EventHandler handler)
 122                 {
 123                         EventHandler component_notifiers;
 124
 125                         if (component == null)
 126                                 throw new ArgumentNullException ("component");
 127
 128                         if (handler == null)
 129                                 throw new ArgumentNullException ("handler");
 130
 131                         if (notifiers == null) return;
 132
 133                         component_notifiers = (EventHandler) notifiers [component];
 134                         component_notifiers -= handler;
 135
 136                         if (component_notifiers == null)
 137                                 notifiers.Remove (component);
 138                         else
 139                                 notifiers [component] = handler;
 140                 }
 141
 142                 protected virtual void OnValueChanged (object component, EventArgs e)
 143                 {
 144                         if (notifiers == null)
 145                                 return;
 146
 147                         EventHandler component_notifiers = (EventHandler) notifiers [component];
 148
 149                         if (component_notifiers == null)
 150                                 return;
 151
 152                         component_notifiers (component, e);
 153                 }
 154
 155                 public abstract object GetValue (object component);
 156
 157                 public abstract void SetValue (object component, object value);
 158
 159                 public abstract void ResetValue (object component);
 160
 161                 public abstract bool CanResetValue (object component);
 162
 163                 public abstract bool ShouldSerializeValue (object component);
 164
 165                 protected object CreateInstance(System.Type type)
 166                 {
 167                         return Assembly.GetExecutingAssembly ().CreateInstance (type.Name);
 168                 }
 169
 170                 public override bool Equals(object obj)
 171                 {
 172                         if (!base.Equals (obj)) return false;
 173                         PropertyDescriptor other = obj as PropertyDescriptor;
 174                         if (other == null) return false;
 175                         return other.PropertyType == PropertyType;
 176                 }
 177
 178                 public PropertyDescriptorCollection GetChildProperties()
 179                 {
 180                         return GetChildProperties (null, null);
 181                 }
 182
 183                 public PropertyDescriptorCollection GetChildProperties(object instance)
 184                 {
 185                         return GetChildProperties (instance, null);
 186                 }
 187
 188                 public PropertyDescriptorCollection GetChildProperties(Attribute[] filter)
 189                 {
 190                         return GetChildProperties (null, filter);
 191                 }
 192
 193                 public override int GetHashCode()
 194                 {
 195                         return base.GetHashCode ();
 196                 }
 197
 198                 public virtual PropertyDescriptorCollection GetChildProperties (object instance, Attribute[] filter)
 199                 {
 200                         return TypeDescriptor.GetProperties (instance, filter);
 201                 }
 202
 203                 public virtual object GetEditor(Type editorBaseType)
 204                 {
 205                         return TypeDescriptor.GetEditor (PropertyType, editorBaseType);
 206                 }
 207
 208                 protected Type GetTypeFromName(string typeName)
 209                 {
 210                         return Type.GetType (typeName);
 211                 }
 212         }
 213 }
 214