/source/library/Interlace/Binding/DelegateBinder.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.Reflection;

using System.Text;



using Interlace.Binding.Views;



#endregion



namespace Interlace.Binding

{

    public delegate void DelegateBinderDelegate<TSender, TProperty>(TSender sender, TProperty value);

    public delegate void DelegateBinderDelegate<TProperty>(TProperty value);

    public delegate void DelegateBinderDelegate();



    public class DelegateBinder

    {

        object _boundTo = null;

        Type _boundToType = null;



        Dictionary<string, List<InternalDelegateBinderDelegate>> _bindings;



        public delegate void InternalDelegateBinderDelegate(object sender, object value);



        public DelegateBinder()

        {

            _bindings = new Dictionary<string, List<InternalDelegateBinderDelegate>>();

        }



        public DelegateBinder(object boundTo)

        : this()

        {

            BoundTo = boundTo;

        }



        public DelegateBinder(Interlace.Binding.Binder boundToBinder, string propertyName)

        : this()

        {

            boundToBinder.AddBinding(propertyName, new PropertyView(this, "BoundTo", null));

        }



        public object BoundTo

        {

            get { return _boundTo; }

            set 

            {

                if (_boundTo == value) return;



                if (_boundTo != null) DisconnectEvents();



                _boundTo = value; 



                if (_boundTo != null)

                {

                    _boundToType = _boundTo.GetType();



                    ConnectEvents();



                    FireAllBindings();

                }

                else

                {

                    _boundToType = null;

                }

            }

        }



        void ConnectEvents()

        {

            if (_boundTo is INotifyPropertyChanged)

            {

                INotifyPropertyChanged notifier = _boundTo as INotifyPropertyChanged;



                notifier.PropertyChanged += new PropertyChangedEventHandler(PropertyChangedEventHandler);

            }

            else

            {

                throw new InvalidOperationException(

                    "The DelegateBinder can only be bound to objects implementing INotifyPropertyChanged.");

            }

        }



        void DisconnectEvents()

        {

            if (_boundTo is INotifyPropertyChanged)

            {

                INotifyPropertyChanged notifier = _boundTo as INotifyPropertyChanged;



                notifier.PropertyChanged -= new PropertyChangedEventHandler(PropertyChangedEventHandler);

            }

            else

            {

                throw new InvalidOperationException();

            }

        }



        void FireAllBindings()

        {

            foreach (string propertyName in _bindings.Keys)

            {

                FireBinding(propertyName);

            }

        }



        void PropertyChangedEventHandler(object sender, PropertyChangedEventArgs e)

        {

            FireBinding(e.PropertyName);

        }



        void FireBinding(string propertyName)

        {

            if (_bindings.ContainsKey(propertyName))

            {

                object value = null;



                PropertyInfo propertyInfo = _boundToType.GetProperty(propertyName);

                if (propertyInfo != null) value = propertyInfo.GetValue(_boundTo, null);



                foreach (InternalDelegateBinderDelegate binderDelegate in _bindings[propertyName])

                {

                    binderDelegate(_boundTo, value);

                }

            }

        }



        public void Bind<TSender, TProperty>(string propertyName, DelegateBinderDelegate<TSender, TProperty> bindTo)

        {

            Bind(propertyName, 

                (InternalDelegateBinderDelegate)delegate(object sender, object value) { bindTo((TSender)sender, (TProperty)value); });

        }



        public void Bind<TProperty>(string propertyName, DelegateBinderDelegate<TProperty> bindTo)

        {

            Bind(propertyName, 

                (InternalDelegateBinderDelegate)delegate(object sender, object value) { bindTo((TProperty)value); });

        }



        public void Bind(string propertyName, DelegateBinderDelegate bindTo)

        {

            Bind(propertyName, 

                (InternalDelegateBinderDelegate)delegate(object sender, object value) { bindTo(); });

        }



        void Bind(string propertyName, InternalDelegateBinderDelegate bindTo)

        {

            if (!_bindings.ContainsKey(propertyName))

            {

                _bindings[propertyName] = new List<InternalDelegateBinderDelegate>();

            }



            _bindings[propertyName].Add(bindTo);

        }

    }

}