src/Tizen.NUI/src/internal/XamlBinding/Interactivity/AttachedCollection.cs

   1 using System;
   2 using System.Collections.Generic;
   3 using System.Collections.ObjectModel;
   4
   5 namespace Tizen.NUI.Binding
   6 {
   7     internal class AttachedCollection<T> : ObservableCollection<T>, ICollection<T>, IAttachedObject where T : BindableObject, IAttachedObject
   8     {
   9         readonly List<WeakReference> _associatedObjects = new List<WeakReference>();
  10
  11         public AttachedCollection()
  12         {
  13         }
  14
  15         public AttachedCollection(IEnumerable<T> collection) : base(collection)
  16         {
  17         }
  18
  19         public AttachedCollection(IList<T> list) : base(list)
  20         {
  21         }
  22
  23         public void AttachTo(BindableObject bindable)
  24         {
  25             if (bindable == null)
  26                 throw new ArgumentNullException("bindable");
  27             OnAttachedTo(bindable);
  28         }
  29
  30         public void DetachFrom(BindableObject bindable)
  31         {
  32             OnDetachingFrom(bindable);
  33         }
  34
  35         protected override void ClearItems()
  36         {
  37             foreach (WeakReference weakbindable in _associatedObjects)
  38             {
  39                 foreach (T item in this)
  40                 {
  41                     var bindable = weakbindable.Target as BindableObject;
  42                     if (bindable == null)
  43                         continue;
  44                     item.DetachFrom(bindable);
  45                 }
  46             }
  47             base.ClearItems();
  48         }
  49
  50         protected override void InsertItem(int index, T item)
  51         {
  52             base.InsertItem(index, item);
  53             foreach (WeakReference weakbindable in _associatedObjects)
  54             {
  55                 var bindable = weakbindable.Target as BindableObject;
  56                 if (bindable == null)
  57                     continue;
  58                 item.AttachTo(bindable);
  59             }
  60         }
  61
  62         protected virtual void OnAttachedTo(BindableObject bindable)
  63         {
  64             lock (_associatedObjects)
  65             {
  66                 _associatedObjects.Add(new WeakReference(bindable));
  67             }
  68             foreach (T item in this)
  69                 item.AttachTo(bindable);
  70         }
  71
  72         protected virtual void OnDetachingFrom(BindableObject bindable)
  73         {
  74             foreach (T item in this)
  75                 item.DetachFrom(bindable);
  76             lock (_associatedObjects)
  77             {
  78                 for (var i = 0; i < _associatedObjects.Count; i++)
  79                 {
  80                     object target = _associatedObjects[i].Target;
  81
  82                     if (target == null || target == bindable)
  83                     {
  84                         _associatedObjects.RemoveAt(i);
  85                         i--;
  86                     }
  87                 }
  88             }
  89         }
  90
  91         protected override void RemoveItem(int index)
  92         {
  93             T item = this[index];
  94             foreach (WeakReference weakbindable in _associatedObjects)
  95             {
  96                 var bindable = weakbindable.Target as BindableObject;
  97                 if (bindable == null)
  98                     continue;
  99                 item.DetachFrom(bindable);
 100             }
 101
 102             base.RemoveItem(index);
 103         }
 104
 105         protected override void SetItem(int index, T item)
 106         {
 107             T old = this[index];
 108             foreach (WeakReference weakbindable in _associatedObjects)
 109             {
 110                 var bindable = weakbindable.Target as BindableObject;
 111                 if (bindable == null)
 112                     continue;
 113                 old.DetachFrom(bindable);
 114             }
 115
 116             base.SetItem(index, item);
 117
 118             foreach (WeakReference weakbindable in _associatedObjects)
 119             {
 120                 var bindable = weakbindable.Target as BindableObject;
 121                 if (bindable == null)
 122                     continue;
 123                 item.AttachTo(bindable);
 124             }
 125         }
 126     }
 127 }