Refactor property changed implementations

Torch/Collections/ObservableDictionary.cs

@@ -12,7 +12,7 @@ using System.Windows.Threading;
 namespace Torch.Collections
 {
     [Serializable]
-    public class ObservableDictionary<TKey, TValue> : ViewModel, IDictionary<TKey, TValue>, INotifyCollectionChanged
+    public class ObservableDictionary<TKey, TValue> : ViewModel, IDictionary<TKey, TValue>
     {
         private IDictionary<TKey, TValue> _internalDict;
 
@@ -37,12 +37,6 @@ namespace Torch.Collections
             };
         }
 
-        /// <inheritdoc />
-        public event NotifyCollectionChangedEventHandler CollectionChanged;
-
-        /// <inheritdoc />
-        public event PropertyChangedEventHandler PropertyChanged;
-
         /// <inheritdoc />
         public IEnumerator<KeyValuePair<TKey, TValue>> GetEnumerator()
         {
@@ -153,26 +147,5 @@ namespace Torch.Collections
 
         /// <inheritdoc />
         public ICollection<TValue> Values => _internalDict.Values;
-
-        private void OnCollectionChanged(NotifyCollectionChangedEventArgs e)
-        {
-            NotifyCollectionChangedEventHandler collectionChanged = CollectionChanged;
-            if (collectionChanged != null)
-                foreach (NotifyCollectionChangedEventHandler nh in collectionChanged.GetInvocationList())
-                {
-                    var dispObj = nh.Target as DispatcherObject;
-
-                    var dispatcher = dispObj?.Dispatcher;
-                    if (dispatcher != null && !dispatcher.CheckAccess())
-                    {
-                        dispatcher.BeginInvoke(
-                            (Action)(() => nh.Invoke(this, new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Reset))),
-                            DispatcherPriority.DataBind);
-                        continue;
-                    }
-
-                    nh.Invoke(this, e);
-                }
-        }
     }
 }

Torch/Collections/ObservableList.cs

@@ -12,16 +12,10 @@ namespace Torch
     /// <summary>
     /// An observable version of <see cref="List{T}"/>.
     /// </summary>
-    public class ObservableList<T> : IList<T>, INotifyCollectionChanged, INotifyPropertyChanged
+    public class ObservableList<T> : ViewModel, IList<T>
     {
         private List<T> _internalList = new List<T>();
 
-        /// <inheritdoc />
-        public event NotifyCollectionChangedEventHandler CollectionChanged;
-
-        /// <inheritdoc />
-        public event PropertyChangedEventHandler PropertyChanged;
-
         /// <inheritdoc />
         public void Clear()
         {
@@ -146,31 +140,6 @@ namespace Torch
             }
         }
 
-        protected void OnCollectionChanged(NotifyCollectionChangedEventArgs e)
-        {
-            var collectionChanged = CollectionChanged;
-            if (collectionChanged != null)
-                foreach (var del in collectionChanged.GetInvocationList())
-                {
-                    var nh = (NotifyCollectionChangedEventHandler)del;
-                    var dispObj = nh.Target as DispatcherObject;
-
-                    var dispatcher = dispObj?.Dispatcher;
-                    if (dispatcher != null && !dispatcher.CheckAccess())
-                    {
-                        dispatcher.BeginInvoke(() => nh.Invoke(this, e), DispatcherPriority.DataBind);
-                        continue;
-                    }
-
-                    nh.Invoke(this, e);
-                }
-        }
-
-        protected void OnPropertyChanged([CallerMemberName] string propertyName = "")
-        {
-            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
-        }
-
         /// <inheritdoc />
         public IEnumerator<T> GetEnumerator()
         {

Torch/Extensions/ICollectionExtensions.cs

@@ -2,6 +2,9 @@
 using System.Collections;
 using System.Collections.Generic;
 using System.Collections.ObjectModel;
+using System.Collections.Specialized;
+using System.ComponentModel;
+using System.Windows.Threading;
 
 namespace Torch
 {
@@ -37,6 +40,63 @@ namespace Torch
             return source as IReadOnlyDictionary<TKey, TValue> ?? new ReadOnlyDictionary<TKey, TValue>(source);
         }
 
+        public static IReadOnlyDictionary<TKey, TValue> AsReadOnlyObservable<TKey, TValue>(this IDictionary<TKey, TValue> source)
+        {
+            if (source == null)
+                throw new ArgumentNullException(nameof(source));
+            return new ObservableReadOnlyDictionary<TKey, TValue>(source);
+        }
+
+        sealed class ObservableReadOnlyDictionary<TKey, TValue> : ViewModel, IReadOnlyDictionary<TKey, TValue>
+        {
+            private readonly IDictionary<TKey, TValue> _dictionary;
+
+            public ObservableReadOnlyDictionary(IDictionary<TKey, TValue> dictionary)
+            {
+                _dictionary = dictionary;
+
+                if (_dictionary is INotifyPropertyChanged p)
+                    p.PropertyChanged += OnPropertyChanged;
+
+                if (_dictionary is INotifyCollectionChanged c)
+                    c.CollectionChanged += OnCollectionChanged;
+            }
+
+            private void OnCollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
+            {
+                OnCollectionChanged(e);
+            }
+
+            private void OnPropertyChanged(object sender, PropertyChangedEventArgs e)
+            {
+                OnPropertyChanged(e.PropertyName);
+            }
+
+            /// <inheritdoc />
+            public IEnumerator<KeyValuePair<TKey, TValue>> GetEnumerator() => _dictionary.GetEnumerator();
+
+            /// <inheritdoc />
+            IEnumerator IEnumerable.GetEnumerator() => ((IEnumerable)_dictionary).GetEnumerator();
+
+            /// <inheritdoc />
+            public int Count => _dictionary.Count;
+
+            /// <inheritdoc />
+            public bool ContainsKey(TKey key) => _dictionary.ContainsKey(key);
+
+            /// <inheritdoc />
+            public bool TryGetValue(TKey key, out TValue value) => _dictionary.TryGetValue(key, out value);
+
+            /// <inheritdoc />
+            public TValue this[TKey key] => _dictionary[key];
+
+            /// <inheritdoc />
+            public IEnumerable<TKey> Keys => _dictionary.Keys;
+
+            /// <inheritdoc />
+            public IEnumerable<TValue> Values => _dictionary.Values;
+        }
+
         sealed class ReadOnlyCollectionAdapter<T> : IReadOnlyCollection<T>
         {
             private readonly ICollection<T> _source;

Torch/ViewModels/ViewModel.cs

@@ -7,21 +7,47 @@ using System.Reflection;
 using System.Runtime.CompilerServices;
 using System.Text;
 using System.Threading.Tasks;
+using System.Windows.Threading;
 
 namespace Torch
 {
     /// <summary>
     /// Provides a method to notify an observer of changes to an object's properties.
     /// </summary>
-    public abstract class ViewModel : INotifyPropertyChanged
+    public abstract class ViewModel : INotifyPropertyChanged, INotifyCollectionChanged
     {
+        /// <inheritdoc />
         public event PropertyChangedEventHandler PropertyChanged;
 
+        /// <inheritdoc />
+        public event NotifyCollectionChangedEventHandler CollectionChanged;
+
         protected virtual void OnPropertyChanged([CallerMemberName] string propName = "")
         {
             PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propName));
         }
 
+        protected virtual void OnCollectionChanged(NotifyCollectionChangedEventArgs e)
+        {
+            NotifyCollectionChangedEventHandler collectionChanged = CollectionChanged;
+            if (collectionChanged != null)
+                foreach (NotifyCollectionChangedEventHandler nh in collectionChanged.GetInvocationList())
+                {
+                    var dispObj = nh.Target as DispatcherObject;
+
+                    var dispatcher = dispObj?.Dispatcher;
+                    if (dispatcher != null && !dispatcher.CheckAccess())
+                    {
+                        dispatcher.BeginInvoke(
+                            (Action)(() => nh.Invoke(this, new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Reset))),
+                            DispatcherPriority.DataBind);
+                        continue;
+                    }
+
+                    nh.Invoke(this, e);
+                }
+        }
+
         protected virtual void SetValue<T>(ref T backingField, T value, [CallerMemberName] string propName = "")
         {
             if (backingField.Equals(value))