/source/library/Interlace/Collections/TrackedBindingList.cs

#region Using Directives and Copyright Notice



// Copyright (c) 2007-2010, Computer Consultancy Pty Ltd

// All rights reserved.

// 

// Redistribution and use in source and binary forms, with or without

// modification, are permitted provided that the following conditions are met:

//     * Redistributions of source code must retain the above copyright

//       notice, this list of conditions and the following disclaimer.

//     * Redistributions in binary form must reproduce the above copyright

//       notice, this list of conditions and the following disclaimer in the

//       documentation and/or other materials provided with the distribution.

//     * Neither the name of the Computer Consultancy Pty Ltd nor the

//       names of its contributors may be used to endorse or promote products

//       derived from this software without specific prior written permission.

// 

// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 

// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 

// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 

// ARE DISCLAIMED. IN NO EVENT SHALL COMPUTER CONSULTANCY PTY LTD BE LIABLE 

// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 

// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR 

// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER 

// CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 

// LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 

// OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH

// DAMAGE.



using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Text;



#endregion



namespace Interlace.Collections

{

    /// <summary>

    /// A binding list that guarantees a call to an event any time an item is added and removed from a list.

    /// </summary>

    /// <typeparam name="T">The type of item in the list.</typeparam>

    /// <remarks>The guarantee is based on the reflected source code; in the current version of the framework,

    /// nothing other than the overridable methods of Collection&lt;T&gt; modifies the list.</remarks>

    public class TrackedBindingList<T> : BindingList<T>

    {

        public event EventHandler<TrackedBindingListEventArgs<T>> Added;

        public event EventHandler<TrackedBindingListEventArgs<T>> Removed;



        protected virtual void OnAdded(T item)

        {

            if (Added != null) Added(this, new TrackedBindingListEventArgs<T>(item));

        }



        protected virtual void OnRemoved(T item)

        {

            if (Removed != null) Removed(this, new TrackedBindingListEventArgs<T>(item));

        }



        protected override void ClearItems()

        {

            foreach (T item in Items)

            {

                OnRemoved(item);

            }



            base.ClearItems();

        }



        protected override void InsertItem(int index, T item)

        {

            base.InsertItem(index, item);



            OnAdded(item);

        }



        protected override void RemoveItem(int index)

        {

            OnRemoved(Items[index]);



            base.RemoveItem(index);

        }



        protected override void SetItem(int index, T item)

        {

            T existingItem = Items[index];



            if (!object.ReferenceEquals(item, existingItem))

            {

                OnRemoved(existingItem);

            }



            base.SetItem(index, item);



            if (!object.ReferenceEquals(item, existingItem))

            {

                OnAdded(item);

            }

        }

    }

}