mcs/class/System/System.ComponentModel/ReflectionPropertyDescriptor.cs

   1 //
   2 // System.ComponentModel.PropertyDescriptor.cs
   3 //
   4 // Author:
   5 //  Lluis Sanchez Gual (lluis@ximian.com)
   6 //
   7 // (C) Novell, Inc.
   8 //
   9
  10 //
  11 // Permission is hereby granted, free of charge, to any person obtaining
  12 // a copy of this software and associated documentation files (the
  13 // "Software"), to deal in the Software without restriction, including
  14 // without limitation the rights to use, copy, modify, merge, publish,
  15 // distribute, sublicense, and/or sell copies of the Software, and to
  16 // permit persons to whom the Software is furnished to do so, subject to
  17 // the following conditions:
  18 //
  19 // The above copyright notice and this permission notice shall be
  20 // included in all copies or substantial portions of the Software.
  21 //
  22 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  23 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  24 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  25 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  26 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  27 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  28 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  29 //
  30
  31 using System;
  32 using System.Collections;
  33 using System.Reflection;
  34 using System.Runtime.InteropServices;
  35 using System.ComponentModel.Design;
  36
  37 namespace System.ComponentModel
  38 {
  39         internal class ReflectionPropertyDescriptor : PropertyDescriptor
  40         {
  41                 PropertyInfo _member;
  42                 Type _type;
  43                 Type _componentType;
  44
  45                 public ReflectionPropertyDescriptor (Type componentType, PropertyDescriptor oldPropertyDescriptor, Attribute [] attributes)
  46                 : base (oldPropertyDescriptor, attributes)
  47                 {
  48                         _type = oldPropertyDescriptor.PropertyType;
  49                         _componentType = componentType;
  50                 }
  51
  52                 public ReflectionPropertyDescriptor (Type componentType, string name, Type type, Attribute [] attributes)
  53                 : base (name, attributes)
  54                 {
  55                         _type = type;
  56                         _componentType = componentType;
  57                 }
  58
  59                 public ReflectionPropertyDescriptor (PropertyInfo info)
  60                 : base (info.Name, (Attribute[])info.GetCustomAttributes (true))
  61                 {
  62                         _member = info;
  63                         _componentType = _member.DeclaringType;
  64                 }
  65
  66                 PropertyInfo GetPropertyInfo ()
  67                 {
  68                         if (_member == null) {
  69                                 _member = _componentType.GetProperty (Name);
  70                                 if (_member == null)
  71                                         throw new ArgumentException ("Accessor methods for the " + Name + " property are missing");
  72                         }
  73                         return _member;
  74                 }
  75
  76                 public override Type ComponentType
  77                 {
  78                         get { return _componentType; }
  79                 }
  80
  81                 public override bool IsReadOnly
  82                 {
  83                         get
  84                         {
  85                                 return !GetPropertyInfo ().CanWrite;
  86                         }
  87                 }
  88
  89                 public override Type PropertyType
  90                 {
  91                         get
  92                         {
  93                                 return GetPropertyInfo ().PropertyType;
  94                         }
  95                 }
  96
  97                 public override object GetValue (object component)
  98                 {
  99                         return GetPropertyInfo ().GetValue (component, null);
 100                 }
 101
 102                 DesignerTransaction CreateTransaction (object obj)
 103                 {
 104                         Component com = obj as Component;
 105                         if (com == null || com.Site == null) return null;
 106
 107                         IDesignerHost dh = (IDesignerHost) com.Site.GetService (typeof(IDesignerHost));
 108                         if (dh == null) return null;
 109
 110                         DesignerTransaction tran = dh.CreateTransaction ();
 111                         IComponentChangeService ccs = (IComponentChangeService) com.Site.GetService (typeof(IComponentChangeService));
 112                         if (ccs != null)
 113                                 ccs.OnComponentChanging (com, this);
 114                         return tran;
 115                 }
 116
 117                 void EndTransaction (object obj, DesignerTransaction tran, object oldValue, object newValue, bool commit)
 118                 {
 119                         if (tran == null) return;
 120
 121                         if (commit) {
 122                                 Component com = obj as Component;
 123                                 IComponentChangeService ccs = (IComponentChangeService) com.Site.GetService (typeof(IComponentChangeService));
 124                                 if (ccs != null)
 125                                         ccs.OnComponentChanged (com, this, oldValue, newValue);
 126                                 tran.Commit ();
 127                         }
 128                         else
 129                                 tran.Cancel ();
 130                 }
 131
 132                 public override void SetValue (object component, object value)
 133                 {
 134                         DesignerTransaction tran = CreateTransaction (component);
 135                         object old = GetValue (component);
 136
 137                         try
 138                         {
 139                                 GetPropertyInfo ().SetValue (component, value, null);
 140                                 EndTransaction (component, tran, old, value, true);
 141                         }
 142                         catch
 143                         {
 144                                 EndTransaction (component, tran, old, value, false);
 145                                 throw;
 146                         }
 147                 }
 148
 149                 public override void ResetValue (object component)
 150                 {
 151                         DefaultValueAttribute attrib = ((DefaultValueAttribute) Attributes[typeof (DefaultValueAttribute)]);
 152                         if (attrib != null) {
 153                                 SetValue (component, attrib.Value);
 154                         }
 155
 156                         DesignerTransaction tran = CreateTransaction (component);
 157                         object old = GetValue (component);
 158
 159                         try
 160                         {
 161                                 MethodInfo mi = component.GetType().GetMethod ("Reset" + Name, Type.EmptyTypes);
 162                                 if (mi != null) mi.Invoke (component, null);
 163                                 EndTransaction (component, tran, old, GetValue (component), true);
 164                         }
 165                         catch
 166                         {
 167                                 EndTransaction (component, tran, old, GetValue (component), false);
 168                                 throw;
 169                         }
 170                 }
 171
 172                 public override bool CanResetValue (object component)
 173                 {
 174                         DefaultValueAttribute attrib = ((DefaultValueAttribute) Attributes[typeof (DefaultValueAttribute)]);
 175                         if (attrib != null) {
 176                                 object current = GetValue (component);
 177                                 if ((attrib.Value == null || current == null) && attrib.Value != current) return true;
 178                                 return !attrib.Value.Equals (current);
 179                         }
 180                         else {
 181                                 MethodInfo mi = component.GetType().GetMethod ("ShouldPersist" + Name, Type.EmptyTypes);
 182                                 if (mi != null) return (bool) mi.Invoke (component, null);
 183                                 mi = component.GetType().GetMethod ("Reset" + Name, Type.EmptyTypes);
 184                                 return (mi != null);
 185                         }
 186                 }
 187
 188                 public override bool ShouldSerializeValue (object component)
 189                 {
 190                         DefaultValueAttribute attrib = ((DefaultValueAttribute) Attributes[typeof (DefaultValueAttribute)]);
 191                         if (attrib != null) {
 192                                 object current = GetValue (component);
 193                                 if ((attrib.Value == null || current == null) && attrib.Value != current) return true;
 194                                 return !attrib.Value.Equals (current);
 195                         }
 196                         else {
 197                                 MethodInfo mi = component.GetType().GetMethod ("ShouldSerialize" + Name, Type.EmptyTypes);
 198                                 if (mi != null) return (bool) mi.Invoke (component, null);
 199                                 return true;
 200                         }
 201                 }
 202         }
 203 }
 204