AnnotationObservableCollection.cs source code in C# .NET

                        Code:
                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / wpf / src / Framework / MS / Internal / Annotations / AnnotationObservableCollection.cs / 1305600 / AnnotationObservableCollection.cs
                        
                        
                            //---------------------------------------------------------------------------- 
//
// 
//    Copyright (C) 2003 by Microsoft Corporation.  All rights reserved.
//  
//
// 
// Description: Subclass of ObservableCollection which also registers for 
//              INotifyPropertyChanged on each of its items (if T implements
//              INotifyPropertyChanged) and passes on the events via the 
//              ItemChanged event.
//
// History:
//  03/10/2005 : rruiz - created 
//
//--------------------------------------------------------------------------- 
 
using System;
using System.Collections; 
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Collections.Specialized;
using System.ComponentModel; 
using System.Diagnostics;
using System.Windows; 
using System.Windows.Data; 

namespace MS.Internal.Annotations 
{
    // An internal extension of INotifyPropertyChanged introduced in order to keep
    // our use of it internal and not publicly expose this interface on our OM.
    internal interface INotifyPropertyChanged2 : INotifyPropertyChanged 
    {
    } 
 
    /// 
    ///  
    internal class AnnotationObservableCollection : ObservableCollection where T : INotifyPropertyChanged2, IOwnedObject
    {
        //-----------------------------------------------------
        // 
        //  Constructors
        // 
        //----------------------------------------------------- 

        #region Constructors 
        /// 
        /// Initializes a new instance of AnnotationObservableCollection that is empty and has default initial capacity.
        /// 
        public AnnotationObservableCollection() : base() 
        {
            _listener = new PropertyChangedEventHandler(OnItemPropertyChanged); 
        } 

        ///  
        /// Initializes a new instance of the AnnotationObservableCollection class
        /// that contains elements copied from the specified list
        /// 
        /// The list whose elements are copied to the new list. 
        /// 
        /// The elements are copied onto the AnnotationObservableCollection in the 
        /// same order they are read by the enumerator of the list. 
        /// 
        ///  list is a null reference  
        public AnnotationObservableCollection(List list) : base(list)
        {
            _listener = new PropertyChangedEventHandler(OnItemPropertyChanged);
        } 

        #endregion Constructors 
 
        //------------------------------------------------------
        // 
        //  Public Events
        //
        //-----------------------------------------------------
 
        //------------------------------------------------------
        // 
        //  Protected Methods 
        //
        //------------------------------------------------------ 

        #region Protected Methods

        ///  
        /// called by base class Collection<T> when the list is being cleared;
        /// raises a CollectionChanged event to any listeners 
        ///  
        protected override void ClearItems()
        { 
            foreach (INotifyPropertyChanged2 item in this)
            {
                SetOwned(item, false);
            } 

            ProtectedClearItems(); 
        } 

        ///  
        /// called by base class Collection<T> when an item is removed from list;
        /// raises a CollectionChanged event to any listeners
        /// 
        protected override void RemoveItem(int index) 
        {
            T removedItem = this[index]; 
 
            SetOwned(removedItem, false);
 
            base.RemoveItem(index);
        }

        ///  
        /// called by base class Collection<T> when an item is added to list;
        /// raises a CollectionChanged event to any listeners 
        ///  
        protected override void InsertItem(int index, T item)
        { 
            if (ItemOwned(item))
                throw new ArgumentException(SR.Get(SRID.AlreadyHasParent));

            base.InsertItem(index, item); 

            SetOwned(item, true); 
        } 

        ///  
        /// called by base class Collection<T> when an item is added to list;
        /// raises a CollectionChanged event to any listeners
        /// 
        protected override void SetItem(int index, T item) 
        {
            if (ItemOwned(item)) 
                throw new ArgumentException(SR.Get(SRID.AlreadyHasParent)); 

            T originalItem = this[index]; 

            SetOwned(originalItem, false);

            ProtectedSetItem(index, item); 

            SetOwned(item, true); 
        } 

        ///  
        ///     Virtual methods allowing subclasses to change the eventing
        ///     behavior for the ClearItems method.  The default behavior
        ///     is to call ObservableCollection's method.
        ///  
        protected virtual void ProtectedClearItems()
        { 
            // Use the standard built-in event 
            base.ClearItems();
        } 

        /// 
        ///     Virtual methods allowing subclasses to change the eventing
        ///     behavior for the SetItem method.  The default behavior 
        ///     is to call Collection's defaut method and fire a single
        ///     event. 
        ///  
        /// index of the item being set
        /// item to set at that index 
        protected virtual void ProtectedSetItem(int index, T item)
        {
            // We only want to fire one event here - this collection contains items that
            // are within a Resource so an assignment means one resource change, period. 
            Items[index] = item;    // directly set Collection inner Items collection
            OnPropertyChanged(new PropertyChangedEventArgs(CountString)); 
            OnPropertyChanged(new PropertyChangedEventArgs(IndexerName)); 
            OnCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Reset));
        } 

        /// 
        ///     Allows subclasses to call superclass's SetItem method without
        ///     any additional functionality added by this class. 
        /// 
        /// index of item being set 
        /// item to set in that index 
        protected void ObservableCollectionSetItem(int index, T item)
        { 
            base.SetItem(index, item);
        }

        // raise CollectionChanged event to any listeners 

 
        ///  
        ///     When an item we contain fires a PropertyChanged event we fire
        ///     a collection changed event letting listeners know the collection 
        ///     has changed in some way.  We don't care about the particulars of
        ///     the event - just want to pass up the chain of objects that something
        ///     has changed.
        ///  
        /// the object whose property changed
        /// the event args describing the property that changed 
        protected virtual void OnItemPropertyChanged(object sender, PropertyChangedEventArgs e) 
        {
            OnCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Reset)); 
        }

        #endregion Protected Methods
 

        //----------------------------------------------------- 
        // 
        //  Private Methods
        // 
        //------------------------------------------------------

        #region Private Methods
 

        // returns whether this item already belongs to a parent object 
        private bool ItemOwned(Object item) 
        {
            if (item != null) 
            {
                IOwnedObject obj = item as IOwnedObject;
                return obj.Owned;
            } 
            return false;
        } 
 
        // sets whether this object belongs to a parent object
        private void SetOwned(Object item, bool owned) 
        {
            if (item != null)
            {
                IOwnedObject obj = item as IOwnedObject; 
                obj.Owned = owned;
 
                if (owned) 
                {
                    ((INotifyPropertyChanged2)item).PropertyChanged += _listener; 
                }
                else
                {
                    ((INotifyPropertyChanged2)item).PropertyChanged -= _listener; 
                }
            } 
        } 

        #endregion Private Methods 

        //-----------------------------------------------------
        //
        //  Private Fields 
        //
        //----------------------------------------------------- 
 
        #region Private & Internal Fields
 
        private readonly PropertyChangedEventHandler _listener = null;
        internal readonly string CountString = "Count";
        internal readonly string IndexerName = "Item[]";
 
        #endregion Private & Internal Fields
    } 
} 

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.
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AnnotationObservableCollection.cs source code in C# .NET

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