Nuclex.Support/Source/Collections/ObservableCollection.cs

131 lines
4.8 KiB
C#

#region CPL License
/*
Nuclex Framework
Copyright (C) 2002-2009 Nuclex Development Labs
This library is free software; you can redistribute it and/or
modify it under the terms of the IBM Common Public License as
published by the IBM Corporation; either version 1.0 of the
License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
IBM Common Public License for more details.
You should have received a copy of the IBM Common Public
License along with this library
*/
#endregion
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
namespace Nuclex.Support.Collections {
/// <summary>Collection which fires events when items are added or removed</summary>
public class ObservableCollection<ItemType> :
Collection<ItemType>, IObservableCollection<ItemType> {
/// <summary>Raised when an item has been added to the collection</summary>
public event EventHandler<ItemEventArgs<ItemType>> ItemAdded;
/// <summary>Raised when an item is removed from the collection</summary>
public event EventHandler<ItemEventArgs<ItemType>> ItemRemoved;
/// <summary>Raised when the collection is about to be cleared</summary>
/// <remarks>
/// This could be covered by calling ItemRemoved for each item currently
/// contained in the collection, but it is often simpler and more efficient
/// 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.
/// </summary>
public ObservableCollection() : base() { }
/// <summary>
/// Initializes a new instance of the ObservableCollection class as a wrapper
/// for the specified list.
/// </summary>
/// <param name="list">The list that is wrapped by the new collection.</param>
/// <exception cref="System.ArgumentNullException">
/// List is null.
/// </exception>
public ObservableCollection(IList<ItemType> list) : base(list) { }
/// <summary>Removes all elements from the Collection</summary>
protected override void ClearItems() {
OnClearing();
base.ClearItems();
OnCleared();
}
/// <summary>
/// Inserts an element into the ObservableCollection 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 ObservableCollection
/// </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<ItemType>(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<ItemType>(item));
}
/// <summary>Fires the 'Clearing' event</summary>
protected virtual void OnClearing() {
if(Clearing != null)
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