mcs/class/System/System.Collections.ObjectModel/ObservableCollection.cs

   1 // Permission is hereby granted, free of charge, to any person obtaining
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   6 // permit persons to whom the Software is furnished to do so, subject to
   7 // the following conditions:
   8 //
   9 // The above copyright notice and this permission notice shall be
  10 // included in all copies or substantial portions of the Software.
  11 //
  12 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  13 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  14 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  15 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  16 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  17 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  18 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  19 //
  20 // Copyright (c) 2007 Novell, Inc. (http://www.novell.com)
  21 // Copyright 2011 Xamarin Inc.
  22 //
  23 // Authors:
  24 //      Chris Toshok (toshok@novell.com)
  25 //      Brian O'Keefe (zer0keefie@gmail.com)
  26 //      Marek Safar (marek.safar@gmail.com)
  27 //
  28
  29 #if NET_4_0 || MOBILE
  30 using System.Collections.Generic;
  31 using System.Collections.Specialized;
  32 using System.ComponentModel;
  33 using System.Runtime.CompilerServices;
  34
  35 namespace System.Collections.ObjectModel
  36 {
  37         [Serializable]
  38 #if !MOBILE
  39         [TypeForwardedFrom (Consts.WindowsBase_3_0)]
  40 #endif
  41         public class ObservableCollection<T> : Collection<T>, INotifyCollectionChanged, INotifyPropertyChanged {
  42                 [Serializable]
  43                 sealed class Reentrant : IDisposable {
  44                         private int count = 0;
  45
  46                         public Reentrant()
  47                         {
  48                         }
  49
  50                         public void Enter()
  51                         {
  52                                 count++;
  53                         }
  54
  55                         public void Dispose()
  56                         {
  57                                 count--;
  58                         }
  59
  60                         public bool Busy
  61                         {
  62                                 get { return count > 0; }
  63                         }
  64                 }
  65
  66                 private Reentrant reentrant = new Reentrant ();
  67
  68                 public ObservableCollection ()
  69                 {
  70                 }
  71
  72                 public ObservableCollection (IEnumerable<T> collection)
  73                 {
  74                         if (collection == null)
  75                                 throw new ArgumentNullException ("collection");
  76
  77                         foreach (var item in collection)
  78                                 Add (item);
  79                 }
  80
  81                 public ObservableCollection (List<T> list)
  82                         : base (list != null ? new List<T> (list) : null)
  83                 {
  84                 }
  85
  86                 public virtual event NotifyCollectionChangedEventHandler CollectionChanged;
  87                 protected virtual event PropertyChangedEventHandler PropertyChanged;
  88
  89                 event PropertyChangedEventHandler INotifyPropertyChanged.PropertyChanged {
  90                         add { this.PropertyChanged += value; }
  91                         remove { this.PropertyChanged -= value; }
  92                 }
  93
  94                 protected IDisposable BlockReentrancy ()
  95                 {
  96                         reentrant.Enter ();
  97                         return reentrant;
  98                 }
  99
 100                 protected void CheckReentrancy ()
 101                 {
 102                         NotifyCollectionChangedEventHandler eh = CollectionChanged;
 103
 104                         // Only have a problem if we have more than one event listener.
 105                         if (reentrant.Busy && eh != null && eh.GetInvocationList ().Length > 1)
 106                                 throw new InvalidOperationException ("Cannot modify the collection while reentrancy is blocked.");
 107                 }
 108
 109                 protected override void ClearItems ()
 110                 {
 111                         CheckReentrancy ();
 112
 113                         base.ClearItems ();
 114
 115                         OnCollectionChanged (new NotifyCollectionChangedEventArgs (NotifyCollectionChangedAction.Reset));
 116                         OnPropertyChanged (new PropertyChangedEventArgs ("Count"));
 117                         OnPropertyChanged (new PropertyChangedEventArgs ("Item[]"));
 118                 }
 119
 120                 protected override void InsertItem (int index, T item)
 121                 {
 122                         CheckReentrancy ();
 123
 124                         base.InsertItem (index, item);
 125
 126                         OnCollectionChanged (new NotifyCollectionChangedEventArgs (NotifyCollectionChangedAction.Add, item, index));
 127                         OnPropertyChanged (new PropertyChangedEventArgs ("Count"));
 128                         OnPropertyChanged (new PropertyChangedEventArgs ("Item[]"));
 129                 }
 130
 131                 public void Move (int oldIndex, int newIndex)
 132                 {
 133                         MoveItem (oldIndex, newIndex);
 134                 }
 135
 136                 protected virtual void MoveItem (int oldIndex, int newIndex)
 137                 {
 138                         CheckReentrancy ();
 139
 140                         T item = Items [oldIndex];
 141                         base.RemoveItem (oldIndex);
 142                         base.InsertItem (newIndex, item);
 143
 144                         OnCollectionChanged (new NotifyCollectionChangedEventArgs (NotifyCollectionChangedAction.Move, item, newIndex, oldIndex));
 145                         OnPropertyChanged (new PropertyChangedEventArgs ("Item[]"));
 146                 }
 147
 148                 protected virtual void OnCollectionChanged (NotifyCollectionChangedEventArgs e)
 149                 {
 150                         NotifyCollectionChangedEventHandler eh = CollectionChanged;
 151
 152                         if (eh != null) {
 153                                 // Make sure that the invocation is done before the collection changes,
 154                                 // Otherwise there's a chance of data corruption.
 155                                 using (BlockReentrancy ()) {
 156                                         eh (this, e);
 157                                 }
 158                         }
 159                 }
 160
 161                 protected virtual void OnPropertyChanged (PropertyChangedEventArgs e)
 162                 {
 163                         PropertyChangedEventHandler eh = PropertyChanged;
 164
 165                         if (eh != null)
 166                                 eh (this, e);
 167                 }
 168
 169                 protected override void RemoveItem (int index)
 170                 {
 171                         CheckReentrancy ();
 172
 173                         T item = Items [index];
 174
 175                         base.RemoveItem (index);
 176
 177                         OnCollectionChanged (new NotifyCollectionChangedEventArgs (NotifyCollectionChangedAction.Remove, item, index));
 178                         OnPropertyChanged (new PropertyChangedEventArgs ("Count"));
 179                         OnPropertyChanged (new PropertyChangedEventArgs ("Item[]"));
 180                 }
 181
 182                 protected override void SetItem (int index, T item)
 183                 {
 184                         CheckReentrancy ();
 185
 186                         T oldItem = Items [index];
 187
 188                         base.SetItem (index, item);
 189
 190                         OnCollectionChanged (new NotifyCollectionChangedEventArgs (NotifyCollectionChangedAction.Replace, item, oldItem, index));
 191                         OnPropertyChanged (new PropertyChangedEventArgs ("Item[]"));
 192                 }
 193         }
 194 }
 195 #endif