mcs/class/referencesource/System.Activities.Presentation/System.Activities.Presentation/System/Activities/Presentation/Model/AttachedProperty.cs

   1 //----------------------------------------------------------------
   2 // Copyright (c) Microsoft Corporation.  All rights reserved.
   3 //----------------------------------------------------------------
   4
   5 namespace System.Activities.Presentation.Model
   6 {
   7     using System;
   8     using System.Collections.Generic;
   9     using System.Linq;
  10     using System.Text;
  11     using System.Activities.Presentation.Model;
  12     using System.Runtime;
  13     using System.Diagnostics.CodeAnalysis;
  14
  15     public abstract class AttachedProperty
  16     {
  17         Type ownerType = typeof(object);
  18
  19         [SuppressMessage("Microsoft.Naming", "CA1721:PropertyNamesShouldNotMatchGetMethods", Justification = "By design.")]
  20         public abstract Type Type
  21         {
  22             get;
  23         }
  24
  25         public abstract bool IsReadOnly
  26         {
  27             get;
  28         }
  29
  30         public bool IsBrowsable
  31         {
  32             get;
  33             set;
  34         }
  35
  36         internal bool IsVisibleToModelItem
  37         {
  38             get;
  39             set;
  40         }
  41
  42         public string Name
  43         {
  44             get; set;
  45         }
  46
  47         public Type OwnerType
  48         {
  49             get
  50             {
  51                 return this.ownerType;
  52             }
  53             set
  54             {
  55                 this.ownerType = value;
  56             }
  57         }
  58
  59         public abstract object GetValue(ModelItem modelItem);
  60         public abstract void SetValue(ModelItem modelItem, object value);
  61         public abstract void ResetValue(ModelItem modelItem);
  62
  63         public void NotifyPropertyChanged(ModelItem modelItem)
  64         {
  65             if (null != modelItem)
  66             {
  67                 ((IModelTreeItem)modelItem).OnPropertyChanged(this.Name);
  68             }
  69         }
  70     }
  71
  72
  73     public class AttachedProperty<T> : AttachedProperty
  74     {
  75         [Fx.Tag.KnownXamlExternal]
  76         public Func<ModelItem, T> Getter
  77         {
  78             get; set;
  79         }
  80
  81         [Fx.Tag.KnownXamlExternal]
  82         public Action<ModelItem, T> Setter
  83         {
  84             get; set;
  85         }
  86
  87         public override Type Type
  88         {
  89             get { return typeof(T); }
  90         }
  91
  92         public override bool IsReadOnly
  93         {
  94             get { return (this.Setter == null); }
  95         }
  96
  97         public override object GetValue(ModelItem modelItem)
  98         {
  99             return this.Getter(modelItem);
 100         }
 101
 102         public override void SetValue(ModelItem modelItem, object Value)
 103         {
 104             if (this.IsReadOnly)
 105             {
 106                 throw FxTrace.Exception.AsError(new InvalidOperationException(SR.PropertyIsReadOnly));
 107             }
 108             this.Setter(modelItem, (T)Value);
 109             this.NotifyPropertyChanged(modelItem);
 110         }
 111
 112         public override void ResetValue(ModelItem modelItem)
 113         {
 114             SetValue(modelItem, default(T));
 115         }
 116     }
 117 }