Extended to IObservableCollection interface with an ItemsCleared event so subscribers observing the collection only to trigger 'Changed' events (versus subscribers observing the collection to wire/unwire themselves from the collection's items) can make use of the collection

git-svn-id: file:///srv/devel/repo-conversion/nusu@182 d2e56fa2-650e-0410-a79f-9358c0239efd

Source/Collections/IObservableCollection.cs

@@ -42,6 +42,9 @@ namespace Nuclex.Support.Collections {
     /// </remarks>
     event EventHandler Clearing;
 
+    /// <summary>Raised when the collection has been cleared of its items</summary>
+    event EventHandler Cleared;
+
   }
 
 } // namespace Nuclex.Support.Collections

Source/Collections/ObservableCollection.Test.cs

@@ -42,6 +42,11 @@ namespace Nuclex.Support.Collections {
       /// <param name="arguments">Not used</param>
       void Clearing(object sender, EventArgs arguments);
 
+      /// <summary>Called when the collection has been cleared of its contents</summary>
+      /// <param name="sender">Collection that was cleared of its contents</param>
+      /// <param name="arguments">Not used</param>
+      void Cleared(object sender, EventArgs arguments);
+
       /// <summary>Called when an item is added to the collection</summary>
       /// <param name="sender">Collection to which an item is being added</param>
       /// <param name="arguments">Contains the item that is being added</param>
@@ -64,7 +69,10 @@ namespace Nuclex.Support.Collections {
       this.mockedSubscriber = this.mockery.NewMock<IObservableCollectionSubscriber>();
 
       this.observedCollection = new ObservableCollection<int>();
-      this.observedCollection.Clearing += new EventHandler(this.mockedSubscriber.Clearing);
+      this.observedCollection.Clearing +=
+        new EventHandler(this.mockedSubscriber.Clearing);
+      this.observedCollection.Cleared +=
+        new EventHandler(this.mockedSubscriber.Cleared);
       this.observedCollection.ItemAdded +=
         new EventHandler<ItemEventArgs<int>>(
           this.mockedSubscriber.ItemAdded
@@ -78,9 +86,8 @@ namespace Nuclex.Support.Collections {
     /// <summary>Tests whether the Clearing event is fired</summary>
     [Test]
     public void TestClearingEvent() {
-      Expect.Once.On(this.mockedSubscriber).
-        Method("Clearing");
-
+      Expect.Once.On(this.mockedSubscriber).Method("Clearing").WithAnyArguments();
+      Expect.Once.On(this.mockedSubscriber).Method("Cleared").WithAnyArguments();
       this.observedCollection.Clear();
 
       this.mockery.VerifyAllExpectationsHaveBeenMet();
@@ -89,9 +96,7 @@ namespace Nuclex.Support.Collections {
     /// <summary>Tests whether the ItemAdded event is fired</summary>
     [Test]
     public void TestItemAddedEvent() {
-      Expect.Once.On(this.mockedSubscriber).
-        Method("ItemAdded").
-        WithAnyArguments();
+      Expect.Once.On(this.mockedSubscriber).Method("ItemAdded").WithAnyArguments();
 
       this.observedCollection.Add(123);
 
@@ -101,15 +106,11 @@ namespace Nuclex.Support.Collections {
     /// <summary>Tests whether the ItemRemoved event is fired</summary>
     [Test]
     public void TestItemRemovedEvent() {
-      Expect.Once.On(this.mockedSubscriber).
-        Method("ItemAdded").
-        WithAnyArguments();
+      Expect.Once.On(this.mockedSubscriber).Method("ItemAdded").WithAnyArguments();
 
       this.observedCollection.Add(123);
 
-      Expect.Once.On(this.mockedSubscriber).
-        Method("ItemRemoved").
-        WithAnyArguments();
+      Expect.Once.On(this.mockedSubscriber).Method("ItemRemoved").WithAnyArguments();
 
       this.observedCollection.Remove(123);
 
@@ -119,28 +120,20 @@ namespace Nuclex.Support.Collections {
     /// <summary>Tests whether items in the collection can be replaced</summary>
     [Test]
     public void TestItemReplacement() {
-      Expect.Exactly(3).On(this.mockedSubscriber).
-        Method("ItemAdded").
-        WithAnyArguments();
+      Expect.Exactly(3).On(this.mockedSubscriber).Method("ItemAdded").WithAnyArguments();
 
       this.observedCollection.Add(1);
       this.observedCollection.Add(2);
       this.observedCollection.Add(3);
 
-      Expect.Once.On(this.mockedSubscriber).
-        Method("ItemRemoved").
-        WithAnyArguments();
-
-      Expect.Once.On(this.mockedSubscriber).
-        Method("ItemAdded").
-        WithAnyArguments();
+      Expect.Once.On(this.mockedSubscriber).Method("ItemRemoved").WithAnyArguments();
+      Expect.Once.On(this.mockedSubscriber).Method("ItemAdded").WithAnyArguments();
 
       // Replace the middle item with something else
       this.observedCollection[1] = 4;
 
       Assert.AreEqual(
-        1,
-        this.observedCollection.IndexOf(4)
+        1, this.observedCollection.IndexOf(4)
       );
 
       this.mockery.VerifyAllExpectationsHaveBeenMet();
@@ -153,10 +146,7 @@ namespace Nuclex.Support.Collections {
 
       ObservableCollection<int> testCollection = new ObservableCollection<int>(integers);
 
-      CollectionAssert.AreEqual(
-        integers,
-        testCollection
-      );
+      CollectionAssert.AreEqual(integers, testCollection);
     }
 
     /// <summary>Mock object factory</summary>

Source/Collections/ObservableCollection.cs

@@ -39,6 +39,8 @@ namespace Nuclex.Support.Collections {
     ///   to process the clearing of the entire collection as a special operation.
     /// </remarks>
     public event EventHandler Clearing;
+    /// <summary>Raised when the collection has been cleared</summary>
+    public event EventHandler Cleared;
 
     /// <summary>
     ///   Initializes a new instance of the ObservableCollection class that is empty.
@@ -58,8 +60,8 @@ namespace Nuclex.Support.Collections {
     /// <summary>Removes all elements from the Collection</summary>
     protected override void ClearItems() {
       OnClearing();
-
       base.ClearItems();
+      OnCleared();
     }
 
     /// <summary>
@@ -71,7 +73,6 @@ namespace Nuclex.Support.Collections {
     /// <param name="item">The zero-based index at which item should be inserted</param>
     protected override void InsertItem(int index, ItemType item) {
       base.InsertItem(index, item);
-
       OnAdded(item);
     }
 
@@ -81,9 +82,7 @@ namespace Nuclex.Support.Collections {
     /// <param name="index">The zero-based index of the element to remove</param>
     protected override void RemoveItem(int index) {
       ItemType item = base[index];
-
       base.RemoveItem(index);
-
       OnRemoved(item);
     }
 
@@ -95,9 +94,7 @@ namespace Nuclex.Support.Collections {
     /// <param name="item">The zero-based index of the element to replace</param>
     protected override void SetItem(int index, ItemType item) {
       ItemType oldItem = base[index];
-
       base.SetItem(index, item);
-
       OnRemoved(oldItem);
       OnAdded(item);
     }
@@ -122,6 +119,12 @@ namespace Nuclex.Support.Collections {
         Clearing(this, EventArgs.Empty);
     }
 
+    /// <summary>Fires the 'Cleared' event</summary>
+    protected virtual void OnCleared() {
+      if(Cleared != null)
+        Cleared(this, EventArgs.Empty);
+    }
+
   }
 
 } // namespace Nuclex.Support.Collections

Source/Collections/ObservableDictionary.Test.cs

@@ -45,6 +45,11 @@ namespace Nuclex.Support.Collections {
       /// <param name="arguments">Not used</param>
       void Clearing(object sender, EventArgs arguments);
 
+      /// <summary>Called when the dictionary has been clear of its contents</summary>
+      /// <param name="sender">Dictionary that was cleared of its contents</param>
+      /// <param name="arguments">Not used</param>
+      void Cleared(object sender, EventArgs arguments);
+
       /// <summary>Called when an item is added to the dictionary</summary>
       /// <param name="sender">Dictionary to which an item is being added</param>
       /// <param name="arguments">Contains the item that is being added</param>
@@ -72,7 +77,10 @@ namespace Nuclex.Support.Collections {
       this.observedDictionary.Add(3, "three");
       this.observedDictionary.Add(42, "forty-two");
 
-      this.observedDictionary.Clearing += new EventHandler(this.mockedSubscriber.Clearing);
+      this.observedDictionary.Clearing +=
+        new EventHandler(this.mockedSubscriber.Clearing);
+      this.observedDictionary.Cleared +=
+        new EventHandler(this.mockedSubscriber.Cleared);
       this.observedDictionary.ItemAdded +=
         new EventHandler<ItemEventArgs<KeyValuePair<int, string>>>(
           this.mockedSubscriber.ItemAdded
@@ -293,6 +301,7 @@ namespace Nuclex.Support.Collections {
     [Test]
     public void TestClearViaIDictionary() {
       Expect.Once.On(this.mockedSubscriber).Method("Clearing").WithAnyArguments();
+      Expect.Once.On(this.mockedSubscriber).Method("Cleared").WithAnyArguments();
       (this.observedDictionary as IDictionary).Clear();
       this.mockery.VerifyAllExpectationsHaveBeenMet();
 
@@ -424,6 +433,7 @@ namespace Nuclex.Support.Collections {
     [Test]
     public void TestClearViaGenericICollection() {
       Expect.Once.On(this.mockedSubscriber).Method("Clearing").WithAnyArguments();
+      Expect.Once.On(this.mockedSubscriber).Method("Cleared").WithAnyArguments();
       (this.observedDictionary as ICollection<KeyValuePair<int, string>>).Clear();
       this.mockery.VerifyAllExpectationsHaveBeenMet();
 

Source/Collections/ObservableDictionary.cs

@@ -76,6 +76,8 @@ namespace Nuclex.Support.Collections {
     public event EventHandler<ItemEventArgs<KeyValuePair<KeyType, ValueType>>> ItemRemoved;
     /// <summary>Raised when the dictionary is about to be cleared</summary>
     public event EventHandler Clearing;
+    /// <summary>Raised when the dictionary has been cleared</summary>
+    public event EventHandler Cleared;
 
     /// <summary>Initializes a new observable dictionary</summary>
     public ObservableDictionary() : this(new Dictionary<KeyType, ValueType>()) { }
@@ -220,6 +222,7 @@ namespace Nuclex.Support.Collections {
     public void Clear() {
       OnClearing();
       this.typedDictionary.Clear();
+      OnCleared();
     }
 
     /// <summary>Fires the 'ItemAdded' event</summary>
@@ -242,6 +245,12 @@ namespace Nuclex.Support.Collections {
         Clearing(this, EventArgs.Empty);
     }
 
+    /// <summary>Fires the 'Cleared' event</summary>
+    protected virtual void OnCleared() {
+      if(Cleared != null)
+        Cleared(this, EventArgs.Empty);
+    }
+
     #region IEnumerable implementation
 
     /// <summary>Returns a new object enumerator for the Dictionary</summary>
@@ -337,6 +346,7 @@ namespace Nuclex.Support.Collections {
     void ICollection<KeyValuePair<KeyType, ValueType>>.Clear() {
       OnClearing();
       this.typedDictionary.Clear();
+      OnCleared();
     }
 
     /// <summary>Removes all items from the Dictionary</summary>