Provided a common class for observable collections similar to what the .NET Framework 3.0 offers; ParentingCollection no longer requires the parent type to be a reference type; Laid the foundation for a new progress tracking framework that can be used to drive progress bars, loading screens and such

git-svn-id: file:///srv/devel/repo-conversion/nusu@9 d2e56fa2-650e-0410-a79f-9358c0239efd

Source/Collections/ObservableCollection.cs

@@ -0,0 +1,109 @@
+using System;
+using System.Collections.Generic;
+using System.Collections.ObjectModel;
+
+namespace Nuclex.Support.Collections {
+
+  /// <summary>Generic collection of progressions</summary>
+  public class ObservableCollection<ItemType> : Collection<ItemType> {
+
+    #region class ItemEventArgs
+
+    /// <summary>Arguments class for events that need to pass a progression</summary>
+    public class ItemEventArgs : EventArgs {
+
+      /// <summary>Initializes a new event arguments supplier</summary>
+      /// <param name="item">Item to be supplied to the event handler</param>
+      public ItemEventArgs(ItemType item) {
+        this.item = item;
+      }
+
+      /// <summary>Obtains the collection item the event arguments are carrying</summary>
+      public ItemType Item {
+        get { return this.item; }
+      }
+
+      /// <summary>Item that's passed to the event handler</summary>
+      private ItemType item;
+
+    }
+
+    #endregion // class ItemEventArgs
+
+    /// <summary>Raised when an item has been added to the collection</summary>
+    public event EventHandler<ItemEventArgs> ItemAdded;
+    /// <summary>Raised when an item is removed from the collection</summary>
+    public event EventHandler<ItemEventArgs> ItemRemoved;
+    /// <summary>Raised the collection is about to be cleared</summary>
+    public event EventHandler Clearing;
+
+    /// <summary>Removes all elements from the Collection</summary>
+    protected override void ClearItems() {
+      OnClearing();
+
+      base.ClearItems();
+    }
+
+    /// <summary>
+    ///   Inserts an element into the ProgressionCollection at the specified index
+    /// </summary>
+    /// <param name="index">
+    ///   The object to insert. The value can be null for reference types.
+    /// </param>
+    /// <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);
+    }
+
+    /// <summary>
+    ///   Removes the element at the specified index of the ProgressionCollection
+    /// </summary>
+    /// <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);
+    }
+
+    /// <summary>Replaces the element at the specified index</summary>
+    /// <param name="index">
+    ///   The new value for the element at the specified index. The value can be null
+    ///   for reference types
+    /// </param>
+    /// <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);
+    }
+
+    /// <summary>Fires the 'ItemAdded' event</summary>
+    /// <param name="item">Item that has been added to the collection</param>
+    protected virtual void OnAdded(ItemType item) {
+      if(ItemAdded != null)
+        ItemAdded(this, new ItemEventArgs(item));
+    }
+
+    /// <summary>Fires the 'ItemRemoved' event</summary>
+    /// <param name="item">Item that has been removed from the collection</param>
+    protected virtual void OnRemoved(ItemType item) {
+      if(ItemRemoved != null)
+        ItemRemoved(this, new ItemEventArgs(item));
+    }
+
+    /// <summary>Fires the 'Clearing' event</summary>
+    protected virtual void OnClearing() {
+      if(Clearing != null)
+        Clearing(this, EventArgs.Empty);
+    }
+
+  }
+
+} // namespace Nuclex.Support.Collections

Source/Collections/Parentable.cs

@@ -5,7 +5,7 @@ namespace Nuclex.Support.Collections {
 
   /// <summary>Base class for objects that can be parented to an owner</summary>
   /// <typeparam name="ParentType">Type of the parent object</typeparam>
-  public class Parentable<ParentType> where ParentType : class {
+  public class Parentable<ParentType> {
 
     /// <summary>Assigns a new parent to this instance</summary>
     internal void SetParent(ParentType parent) {

Source/Collections/ParentingCollection.cs

@@ -15,8 +15,7 @@ namespace Nuclex.Support.Collections {
   /// <typeparam name="ParentType">Type of the parent object to assign to items</typeparam>
   /// <typeparam name="ItemType">Type of the items being managed in the collection</typeparam>
   public class ParentingCollection<ParentType, ItemType> : Collection<ItemType>
-    where ItemType : Parentable<ParentType>
-    where ParentType : class {
+    where ItemType : Parentable<ParentType> {
 
     /// <summary>Reparents all elements in the collection</summary>
     /// <param name="parent">New parent to take ownership of the items</param>
@@ -30,7 +29,7 @@ namespace Nuclex.Support.Collections {
     /// <summary>Clears all elements from the collection</summary>
     protected override void ClearItems() {
       for(int index = 0; index < Count; ++index)
-        base[index].SetParent(null);
+        base[index].SetParent(default(ParentType));
 
       base.ClearItems();
     }
@@ -46,7 +45,7 @@ namespace Nuclex.Support.Collections {
     /// <summary>Removes an element from the collection</summary>
     /// <param name="index">Index of the element to remove</param>
     protected override void RemoveItem(int index) {
-      base[index].SetParent(null);
+      base[index].SetParent(default(ParentType));
       base.RemoveItem(index);
     }
 
@@ -70,7 +69,7 @@ namespace Nuclex.Support.Collections {
       if(disposeItems) {
 
         // Have the items do their cleanup work
-        Reparent(null);
+        Reparent(default(ParentType));
 
         // Dispose of all the items in the collection that implement IDisposable
         foreach(ItemType item in this) {