/source/library/Interlace/Binding/CountBinderModel.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;

using System.Collections.Generic;

using System.ComponentModel;

using System.Reflection;

using System.Text;



#endregion



namespace Interlace.Binding

{

    public class CountBinderModel : IBinderModel

    {

        ICollection _boundTo;

        Type _boundToType;



        private BinderController _controller;



        public CountBinderModel()

        {

            _boundTo = null;

        }



        public BinderController Controller

        {

            set { _controller = value; }

        }



        public string GetDescriptionForTracing()

        {

            if (_boundTo == null) return "Count of null";



            return string.Format("Count of \"{0}\", type \"{1}\"",

                _boundTo, _boundToType.Name);

        }



        private void ConnectEvents()

        {

            EventInfo changeEvent = _boundToType.GetEvent("ListChanged");



            if (changeEvent != null)

            {

                changeEvent.AddEventHandler(_boundTo, new ListChangedEventHandler(ListChangedEventHandler));

            }

        }



        private void DisconnectEvents()

        {

            EventInfo changeEvent = _boundToType.GetEvent("ListChanged");



            if (changeEvent != null)

            {

                changeEvent.RemoveEventHandler(_boundTo, new ListChangedEventHandler(ListChangedEventHandler));

            }

        }



        public void ConnectBoundToObject(object boundTo)

        {

            if (_boundTo != null) DisconnectEvents();



            _boundTo = boundTo as ICollection;



            if (_boundTo != null)

            {

                _boundToType = _boundTo.GetType();

                ConnectEvents();

            }



            _controller.OnModelModified();

        }



        public void DisconnectBoundToObject()

        {

            if (_boundTo != null)

            {

                DisconnectEvents();

            }



            _boundTo = null;

            _boundToType = null;



            _controller.OnModelModified();

        }



        private void ListChangedEventHandler(object sender, ListChangedEventArgs e)

        {

            switch (e.ListChangedType)

            {

                case ListChangedType.ItemChanged:

                case ListChangedType.ItemMoved:

                case ListChangedType.PropertyDescriptorAdded:

                case ListChangedType.PropertyDescriptorChanged:

                case ListChangedType.PropertyDescriptorDeleted:

                    // Ignore these events for the count.

                    return;



                default:

                    _controller.OnModelModified();

                    break;

            }

        }



        public object GetValue()

        {

            if (_boundTo == null) return BinderNotBound.Value;



            return _boundTo.Count;

        }



        public void SetValue(object value)

        {

            return;

        }

    }

}