Я хочу иметь возможность добавлять диапазон и обновляться для всего объема.
Я также хочу иметь возможность отменить действие до его совершения (т.е. изменение коллекции, кроме "измененного" ).
Связанный Q Какая коллекция .Net для одновременного добавления нескольких объектов и получения уведомления?
Прежде всего, проголосуйте и прокомментируйте запрос API в репозитории.NET.
Вот моя оптимизированная версия ObservableRangeCollection (оптимизированная версия Джеймса Montemagno один).
Он работает очень быстро и предназначен для повторного использования существующих элементов, когда это возможно, и избегать ненужных событий или, если это возможно, их доработки до одного. Метод ReplaceRange заменяет/удаляет/добавляет необходимые элементы по соответствующим индексам и разбивает возможные события.
Протестировано на пользовательском интерфейсе Xamarin.Forms с отличными результатами для очень частых обновлений большой коллекции (5-7 обновлений в секунду).
Примечание. Поскольку WPF не привык работать с операциями с диапазоном, он будет генерировать NotSupportedException при использовании ObservableRangeCollection из ниже в работе, связанной с интерфейсом WPF, например, привязать ее к ListBox и т.д. (Вы все равно можете использовать ObservableRangeCollection<T> если не привязаны к UI).
Однако вы можете использовать WpfObservableRangeCollection<T> решение WpfObservableRangeCollection<T>.
Реальное решение будет создавать CollectionView который знает, как справляться с операциями с диапазоном, но у меня все еще не было времени для его реализации.
RAW Code - открыть как Raw, затем сделать Ctrl + A, чтобы выбрать все, а затем Ctrl + C для копирования.
// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
using System.Collections.Generic;
using System.Collections.Specialized;
using System.ComponentModel;
using System.Diagnostics;
namespace System.Collections.ObjectModel
{
/// <summary>
/// Implementation of a dynamic data collection based on generic Collection<T>,
/// implementing INotifyCollectionChanged to notify listeners
/// when items get added, removed or the whole list is refreshed.
/// </summary>
public class ObservableRangeCollection<T> : ObservableCollection<T>
{
//------------------------------------------------------
//
// Private Fields
//
//------------------------------------------------------
#region Private Fields
[NonSerialized]
private DeferredEventsCollection _deferredEvents;
#endregion Private Fields
//------------------------------------------------------
//
// Constructors
//
//------------------------------------------------------
#region Constructors
/// <summary>
/// Initializes a new instance of ObservableCollection that is empty and has default initial capacity.
/// </summary>
public ObservableRangeCollection() { }
/// <summary>
/// Initializes a new instance of the ObservableCollection class that contains
/// elements copied from the specified collection and has sufficient capacity
/// to accommodate the number of elements copied.
/// </summary>
/// <param name="collection">The collection whose elements are copied to the new list.</param>
/// <remarks>
/// The elements are copied onto the ObservableCollection in the
/// same order they are read by the enumerator of the collection.
/// </remarks>
/// <exception cref="ArgumentNullException"> collection is a null reference </exception>
public ObservableRangeCollection(IEnumerable<T> collection) : base(collection) { }
/// <summary>
/// Initializes a new instance of the ObservableCollection class
/// that contains elements copied from the specified list
/// </summary>
/// <param name="list">The list whose elements are copied to the new list.</param>
/// <remarks>
/// The elements are copied onto the ObservableCollection in the
/// same order they are read by the enumerator of the list.
/// </remarks>
/// <exception cref="ArgumentNullException"> list is a null reference </exception>
public ObservableRangeCollection(List<T> list) : base(list) { }
#endregion Constructors
//------------------------------------------------------
//
// Public Methods
//
//------------------------------------------------------
#region Public Methods
/// <summary>
/// Adds the elements of the specified collection to the end of the <see cref="ObservableCollection{T}"/>.
/// </summary>
/// <param name="collection">
/// The collection whose elements should be added to the end of the <see cref="ObservableCollection{T}"/>.
/// The collection itself cannot be null, but it can contain elements that are null, if type T is a reference type.
/// </param>
/// <exception cref="ArgumentNullException"><paramref name="collection"/> is null.</exception>
public void AddRange(IEnumerable<T> collection)
{
InsertRange(Count, collection);
}
/// <summary>
/// Inserts the elements of a collection into the <see cref="ObservableCollection{T}"/> at the specified index.
/// </summary>
/// <param name="index">The zero-based index at which the new elements should be inserted.</param>
/// <param name="collection">The collection whose elements should be inserted into the List<T>.
/// The collection itself cannot be null, but it can contain elements that are null, if type T is a reference type.</param>
/// <exception cref="ArgumentNullException"><paramref name="collection"/> is null.</exception>
/// <exception cref="ArgumentOutOfRangeException"><paramref name="index"/> is not in the collection range.</exception>
public void InsertRange(int index, IEnumerable<T> collection)
{
if (collection == null)
throw new ArgumentNullException(nameof(collection));
if (index < 0)
throw new ArgumentOutOfRangeException(nameof(index));
if (index > Count)
throw new ArgumentOutOfRangeException(nameof(index));
if (collection is ICollection<T> countable)
{
if (countable.Count == 0)
{
return;
}
}
else if (!ContainsAny(collection))
{
return;
}
CheckReentrancy();
//expand the following couple of lines when adding more constructors.
var target = (List<T>)Items;
target.InsertRange(index, collection);
OnEssentialPropertiesChanged();
if (!(collection is IList list))
list = new List<T>(collection);
OnCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Add, list, index));
}
/// <summary>
/// Removes the first occurence of each item in the specified collection from the <see cref="ObservableCollection{T}"/>.
/// </summary>
/// <param name="collection">The items to remove.</param>
/// <exception cref="ArgumentNullException"><paramref name="collection"/> is null.</exception>
public void RemoveRange(IEnumerable<T> collection)
{
if (collection == null)
throw new ArgumentNullException(nameof(collection));
if (Count == 0)
{
return;
}
else if (collection is ICollection<T> countable)
{
if (countable.Count == 0)
return;
else if (countable.Count == 1)
using (IEnumerator<T> enumerator = countable.GetEnumerator())
{
enumerator.MoveNext();
Remove(enumerator.Current);
return;
}
}
else if (!(ContainsAny(collection)))
{
return;
}
CheckReentrancy();
var clusters = new Dictionary<int, List<T>>();
var lastIndex = -1;
List<T> lastCluster = null;
foreach (T item in collection)
{
var index = IndexOf(item);
if (index < 0)
{
continue;
}
Items.RemoveAt(index);
if (lastIndex == index && lastCluster != null)
{
lastCluster.Add(item);
}
else
{
clusters[lastIndex = index] = lastCluster = new List<T> { item };
}
}
OnEssentialPropertiesChanged();
if (Count == 0)
OnCollectionReset();
else
foreach (KeyValuePair<int, List<T>> cluster in clusters)
OnCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Remove, cluster.Value, cluster.Key));
}
/// <summary>
/// Iterates over the collection and removes all items that satisfy the specified match.
/// </summary>
/// <remarks>The complexity is O(n).</remarks>
/// <param name="match"></param>
/// <returns>Returns the number of elements that where </returns>
/// <exception cref="ArgumentNullException"><paramref name="match"/> is null.</exception>
public int RemoveAll(Predicate<T> match)
{
return RemoveAll(0, Count, match);
}
/// <summary>
/// Iterates over the specified range within the collection and removes all items that satisfy the specified match.
/// </summary>
/// <remarks>The complexity is O(n).</remarks>
/// <param name="index">The index of where to start performing the search.</param>
/// <param name="count">The number of items to iterate on.</param>
/// <param name="match"></param>
/// <returns>Returns the number of elements that where </returns>
/// <exception cref="ArgumentOutOfRangeException"><paramref name="index"/> is out of range.</exception>
/// <exception cref="ArgumentOutOfRangeException"><paramref name="count"/> is out of range.</exception>
/// <exception cref="ArgumentNullException"><paramref name="match"/> is null.</exception>
public int RemoveAll(int index, int count, Predicate<T> match)
{
if (index < 0)
throw new ArgumentOutOfRangeException(nameof(index));
if (count < 0)
throw new ArgumentOutOfRangeException(nameof(count));
if (index + count > Count)
throw new ArgumentOutOfRangeException(nameof(index));
if (match == null)
throw new ArgumentNullException(nameof(match));
if (Count == 0)
return 0;
List<T> cluster = null;
var clusterIndex = -1;
var removedCount = 0;
using (BlockReentrancy())
using (DeferEvents())
{
for (var i = 0; i < count; i++, index++)
{
T item = Items[index];
if (match(item))
{
Items.RemoveAt(index);
removedCount++;
if (clusterIndex == index)
{
Debug.Assert(cluster != null);
cluster.Add(item);
}
else
{
cluster = new List<T> { item };
clusterIndex = index;
}
index--;
}
else if (clusterIndex > -1)
{
OnCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Remove, cluster, clusterIndex));
clusterIndex = -1;
cluster = null;
}
}
if (clusterIndex > -1)
OnCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Remove, cluster, clusterIndex));
}
if (removedCount > 0)
OnEssentialPropertiesChanged();
return removedCount;
}
/// <summary>
/// Removes a range of elements from the <see cref="ObservableCollection{T}"/>>.
/// </summary>
/// <param name="index">The zero-based starting index of the range of elements to remove.</param>
/// <param name="count">The number of elements to remove.</param>
/// <exception cref="ArgumentOutOfRangeException">The specified range is exceeding the collection.</exception>
public void RemoveRange(int index, int count)
{
if (index < 0)
throw new ArgumentOutOfRangeException(nameof(index));
if (count < 0)
throw new ArgumentOutOfRangeException(nameof(count));
if (index + count > Count)
throw new ArgumentOutOfRangeException(nameof(index));
if (count == 0)
return;
if (count == 1)
{
RemoveItem(index);
return;
}
//Items will always be List<T>, see constructors
var items = (List<T>)Items;
List<T> removedItems = items.GetRange(index, count);
CheckReentrancy();
items.RemoveRange(index, count);
OnEssentialPropertiesChanged();
if (Count == 0)
OnCollectionReset();
else
OnCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Remove, removedItems, index));
}
/// <summary>
/// Clears the current collection and replaces it with the specified collection,
/// using the default <see cref="EqualityComparer{T}"/>.
/// </summary>
/// <param name="collection">The items to fill the collection with, after clearing it.</param>
/// <exception cref="ArgumentNullException"><paramref name="collection"/> is null.</exception>
public void ReplaceRange(IEnumerable<T> collection)
{
ReplaceRange(0, Count, collection, EqualityComparer<T>.Default);
}
/// <summary>
/// Clears the current collection and replaces it with the specified collection,
/// using the specified comparer to skip equal items.
/// </summary>
/// <param name="collection">The items to fill the collection with, after clearing it.</param>
/// <param name="comparer">An <see cref="IEqualityComparer{T}"/> to be used
/// to check whether an item in the same location already existed before,
/// which in case it would not be added to the collection, and no event will be raised for it.</param>
/// <exception cref="ArgumentNullException"><paramref name="collection"/> is null.</exception>
/// <exception cref="ArgumentNullException"><paramref name="comparer"/> is null.</exception>
public void ReplaceRange(IEnumerable<T> collection, IEqualityComparer<T> comparer)
{
ReplaceRange(0, Count, collection, comparer);
}
/// <summary>
/// Removes the specified range and inserts the specified collection,
/// ignoring equal items (using <see cref="EqualityComparer{T}.Default"/>).
/// </summary>
/// <param name="index">The index of where to start the replacement.</param>
/// <param name="count">The number of items to be replaced.</param>
/// <param name="collection">The collection to insert in that location.</param>
/// <exception cref="ArgumentOutOfRangeException"><paramref name="index"/> is out of range.</exception>
/// <exception cref="ArgumentOutOfRangeException"><paramref name="count"/> is out of range.</exception>
/// <exception cref="ArgumentNullException"><paramref name="collection"/> is null.</exception>
public void ReplaceRange(int index, int count, IEnumerable<T> collection)
{
ReplaceRange(index, count, collection, EqualityComparer<T>.Default);
}
/// <summary>
/// Removes the specified range and inserts the specified collection in its position, leaving equal items in equal positions intact.
/// </summary>
/// <param name="index">The index of where to start the replacement.</param>
/// <param name="count">The number of items to be replaced.</param>
/// <param name="collection">The collection to insert in that location.</param>
/// <param name="comparer">The comparer to use when checking for equal items.</param>
/// <exception cref="ArgumentOutOfRangeException"><paramref name="index"/> is out of range.</exception>
/// <exception cref="ArgumentOutOfRangeException"><paramref name="count"/> is out of range.</exception>
/// <exception cref="ArgumentNullException"><paramref name="collection"/> is null.</exception>
/// <exception cref="ArgumentNullException"><paramref name="comparer"/> is null.</exception>
public void ReplaceRange(int index, int count, IEnumerable<T> collection, IEqualityComparer<T> comparer)
{
if (index < 0)
throw new ArgumentOutOfRangeException(nameof(index));
if (count < 0)
throw new ArgumentOutOfRangeException(nameof(count));
if (index + count > Count)
throw new ArgumentOutOfRangeException(nameof(index));
if (collection == null)
throw new ArgumentNullException(nameof(collection));
if (comparer == null)
throw new ArgumentNullException(nameof(comparer));
if (collection is ICollection<T> countable)
{
if (countable.Count == 0)
{
RemoveRange(index, count);
return;
}
}
else if (!ContainsAny(collection))
{
RemoveRange(index, count);
return;
}
if (index + count == 0)
{
InsertRange(0, collection);
return;
}
if (!(collection is IList<T> list))
list = new List<T>(collection);
using (BlockReentrancy())
using (DeferEvents())
{
var rangeCount = index + count;
var addedCount = list.Count;
var changesMade = false;
List<T>
newCluster = null,
oldCluster = null;
int i = index;
for (; i < rangeCount && i - index < addedCount; i++)
{
//parallel position
T old = this[i], @new = list[i - index];
if (comparer.Equals(old, @new))
{
OnRangeReplaced(i, newCluster, oldCluster);
continue;
}
else
{
Items[i] = @new;
if (newCluster == null)
{
Debug.Assert(oldCluster == null);
newCluster = new List<T> { @new };
oldCluster = new List<T> { old };
}
else
{
newCluster.Add(@new);
oldCluster.Add(old);
}
changesMade = true;
}
}
OnRangeReplaced(i, newCluster, oldCluster);
//exceeding position
if (count != addedCount)
{
var items = (List<T>)Items;
if (count > addedCount)
{
var removedCount = rangeCount - addedCount;
T[] removed = new T[removedCount];
items.CopyTo(i, removed, 0, removed.Length);
items.RemoveRange(i, removedCount);
OnCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Remove, removed, i));
}
else
{
var k = i - index;
T[] added = new T[addedCount - k];
for (int j = k; j < addedCount; j++)
{
T @new = list[j];
added[j - k] = @new;
}
items.InsertRange(i, added);
OnCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Add, added, i));
}
OnEssentialPropertiesChanged();
}
else if (changesMade)
{
OnIndexerPropertyChanged();
}
}
}
#endregion Public Methods
//------------------------------------------------------
//
// Protected Methods
//
//------------------------------------------------------
#region Protected Methods
/// <summary>
/// Called by base class Collection<T> when the list is being cleared;
/// raises a CollectionChanged event to any listeners.
/// </summary>
protected override void ClearItems()
{
if (Count == 0)
return;
CheckReentrancy();
base.ClearItems();
OnEssentialPropertiesChanged();
OnCollectionReset();
}
/// <summary>
/// Called by base class Collection<T> when an item is set in list;
/// raises a CollectionChanged event to any listeners.
/// </summary>
protected override void SetItem(int index, T item)
{
if (Equals(this[index], item))
return;
CheckReentrancy();
T originalItem = this[index];
base.SetItem(index, item);
OnIndexerPropertyChanged();
OnCollectionChanged(NotifyCollectionChangedAction.Replace, originalItem, item, index);
}
/// <summary>
/// Raise CollectionChanged event to any listeners.
/// Properties/methods modifying this ObservableCollection will raise
/// a collection changed event through this virtual method.
/// </summary>
/// <remarks>
/// When overriding this method, either call its base implementation
/// or call <see cref="BlockReentrancy"/> to guard against reentrant collection changes.
/// </remarks>
protected override void OnCollectionChanged(NotifyCollectionChangedEventArgs e)
{
if (_deferredEvents != null)
{
_deferredEvents.Add(e);
return;
}
base.OnCollectionChanged(e);
}
protected virtual IDisposable DeferEvents() => new DeferredEventsCollection(this);
#endregion Protected Methods
//------------------------------------------------------
//
// Private Methods
//
//------------------------------------------------------
#region Private Methods
/// <summary>
/// Helper function to determine if a collection contains any elements.
/// </summary>
/// <param name="collection">The collection to evaluate.</param>
/// <returns></returns>
private static bool ContainsAny(IEnumerable<T> collection)
{
using (IEnumerator<T> enumerator = collection.GetEnumerator())
return enumerator.MoveNext();
}
/// <summary>
/// Helper to raise Count property and the Indexer property.
/// </summary>
private void OnEssentialPropertiesChanged()
{
OnPropertyChanged(EventArgsCache.CountPropertyChanged);
OnIndexerPropertyChanged();
}
/// <summary>
/// /// Helper to raise a PropertyChanged event for the Indexer property
/// /// </summary>
private void OnIndexerPropertyChanged() =>
OnPropertyChanged(EventArgsCache.IndexerPropertyChanged);
/// <summary>
/// Helper to raise CollectionChanged event to any listeners
/// </summary>
private void OnCollectionChanged(NotifyCollectionChangedAction action, object oldItem, object newItem, int index) =>
OnCollectionChanged(new NotifyCollectionChangedEventArgs(action, newItem, oldItem, index));
/// <summary>
/// Helper to raise CollectionChanged event with action == Reset to any listeners
/// </summary>
private void OnCollectionReset() =>
OnCollectionChanged(EventArgsCache.ResetCollectionChanged);
/// <summary>
/// Helper to raise event for clustered action and clear cluster.
/// </summary>
/// <param name="followingItemIndex">The index of the item following the replacement block.</param>
/// <param name="newCluster"></param>
/// <param name="oldCluster"></param>
//TODO should have really been a local method inside ReplaceRange(int index, int count, IEnumerable<T> collection, IEqualityComparer<T> comparer),
//move when supported language version updated.
private void OnRangeReplaced(int followingItemIndex, ICollection<T> newCluster, ICollection<T> oldCluster)
{
if (oldCluster == null || oldCluster.Count == 0)
{
Debug.Assert(newCluster == null || newCluster.Count == 0);
return;
}
OnCollectionChanged(
new NotifyCollectionChangedEventArgs(
NotifyCollectionChangedAction.Replace,
new List<T>(newCluster),
new List<T>(oldCluster),
followingItemIndex - oldCluster.Count));
oldCluster.Clear();
newCluster.Clear();
}
#endregion Private Methods
//------------------------------------------------------
//
// Private Types
//
//------------------------------------------------------
#region Private Types
private sealed class DeferredEventsCollection : List<NotifyCollectionChangedEventArgs>, IDisposable
{
private readonly ObservableRangeCollection<T> _collection;
public DeferredEventsCollection(ObservableRangeCollection<T> collection)
{
Debug.Assert(collection != null);
Debug.Assert(collection._deferredEvents == null);
_collection = collection;
_collection._deferredEvents = this;
}
public void Dispose()
{
_collection._deferredEvents = null;
foreach (var args in this)
_collection.OnCollectionChanged(args);
}
}
#endregion Private Types
}
/// <remarks>
/// To be kept outside <see cref="ObservableCollection{T}"/>, since otherwise, a new instance will be created for each generic type used.
/// </remarks>
internal static class EventArgsCache
{
internal static readonly PropertyChangedEventArgs CountPropertyChanged = new PropertyChangedEventArgs("Count");
internal static readonly PropertyChangedEventArgs IndexerPropertyChanged = new PropertyChangedEventArgs("Item[]");
internal static readonly NotifyCollectionChangedEventArgs ResetCollectionChanged = new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Reset);
}
}
Обратитесь к обновленной и оптимизированной версии С# 7. Я не хотел удалять версию VB.NET, поэтому я просто разместил ее в отдельном ответе.
Кажется, он не поддерживается, я реализовал сам, FYI, надеюсь, что это будет полезно:
Я обновил версию VB, и теперь она вызывает событие перед изменением коллекции, поэтому вы можете пожалеть (полезно при использовании с DataGrid, ListView и многими другими, что вы можете показать "Are you sure" подтверждение для пользователя), обновленная версия VB находится в нижней части этого сообщения.
Примите мои извинения, что экран слишком узкий, чтобы содержать мой код, мне он тоже не нравится.
VB.NET:
Imports System.Collections.Specialized
Namespace System.Collections.ObjectModel
''' <summary>
''' Represents a dynamic data collection that provides notifications when items get added, removed, or when the whole list is refreshed.
''' </summary>
''' <typeparam name="T"></typeparam>
Public Class ObservableRangeCollection(Of T) : Inherits System.Collections.ObjectModel.ObservableCollection(Of T)
''' <summary>
''' Adds the elements of the specified collection to the end of the ObservableCollection(Of T).
''' </summary>
Public Sub AddRange(ByVal collection As IEnumerable(Of T))
For Each i In collection
Items.Add(i)
Next
OnCollectionChanged(New NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Reset))
End Sub
''' <summary>
''' Removes the first occurence of each item in the specified collection from ObservableCollection(Of T).
''' </summary>
Public Sub RemoveRange(ByVal collection As IEnumerable(Of T))
For Each i In collection
Items.Remove(i)
Next
OnCollectionChanged(New NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Reset))
End Sub
''' <summary>
''' Clears the current collection and replaces it with the specified item.
''' </summary>
Public Sub Replace(ByVal item As T)
ReplaceRange(New T() {item})
End Sub
''' <summary>
''' Clears the current collection and replaces it with the specified collection.
''' </summary>
Public Sub ReplaceRange(ByVal collection As IEnumerable(Of T))
Dim old = Items.ToList
Items.Clear()
For Each i In collection
Items.Add(i)
Next
OnCollectionChanged(New NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Reset))
End Sub
''' <summary>
''' Initializes a new instance of the System.Collections.ObjectModel.ObservableCollection(Of T) class.
''' </summary>
''' <remarks></remarks>
Public Sub New()
MyBase.New()
End Sub
''' <summary>
''' Initializes a new instance of the System.Collections.ObjectModel.ObservableCollection(Of T) class that contains elements copied from the specified collection.
''' </summary>
''' <param name="collection">collection: The collection from which the elements are copied.</param>
''' <exception cref="System.ArgumentNullException">The collection parameter cannot be null.</exception>
Public Sub New(ByVal collection As IEnumerable(Of T))
MyBase.New(collection)
End Sub
End Class
End Namespace
С#
using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Collections.Specialized;
using System.Linq;
/// <summary>
/// Represents a dynamic data collection that provides notifications when items get added, removed, or when the whole list is refreshed.
/// </summary>
/// <typeparam name="T"></typeparam>
public class ObservableRangeCollection<T> : ObservableCollection<T>
{
/// <summary>
/// Adds the elements of the specified collection to the end of the ObservableCollection(Of T).
/// </summary>
public void AddRange(IEnumerable<T> collection)
{
if (collection == null) throw new ArgumentNullException("collection");
foreach (var i in collection) Items.Add(i);
OnCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Reset));
}
/// <summary>
/// Removes the first occurence of each item in the specified collection from ObservableCollection(Of T).
/// </summary>
public void RemoveRange(IEnumerable<T> collection)
{
if (collection == null) throw new ArgumentNullException("collection");
foreach (var i in collection) Items.Remove(i);
OnCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Reset));
}
/// <summary>
/// Clears the current collection and replaces it with the specified item.
/// </summary>
public void Replace(T item)
{
ReplaceRange(new T[] { item });
}
/// <summary>
/// Clears the current collection and replaces it with the specified collection.
/// </summary>
public void ReplaceRange(IEnumerable<T> collection)
{
if (collection == null) throw new ArgumentNullException("collection");
Items.Clear();
foreach (var i in collection) Items.Add(i);
OnCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Reset));
}
/// <summary>
/// Initializes a new instance of the System.Collections.ObjectModel.ObservableCollection(Of T) class.
/// </summary>
public ObservableRangeCollection()
: base() { }
/// <summary>
/// Initializes a new instance of the System.Collections.ObjectModel.ObservableCollection(Of T) class that contains elements copied from the specified collection.
/// </summary>
/// <param name="collection">collection: The collection from which the elements are copied.</param>
/// <exception cref="System.ArgumentNullException">The collection parameter cannot be null.</exception>
public ObservableRangeCollection(IEnumerable<T> collection)
: base(collection) { }
}
Imports System.Collections.Specialized
Imports System.ComponentModel
Imports System.Collections.ObjectModel
Public Class ObservableRangeCollection(Of T) : Inherits ObservableCollection(Of T) : Implements INotifyCollectionChanging(Of T)
''' <summary>
''' Initializes a new instance of the System.Collections.ObjectModel.ObservableCollection(Of T) class.
''' </summary>
''' <remarks></remarks>
Public Sub New()
MyBase.New()
End Sub
''' <summary>
''' Initializes a new instance of the System.Collections.ObjectModel.ObservableCollection(Of T) class that contains elements copied from the specified collection.
''' </summary>
''' <param name="collection">collection: The collection from which the elements are copied.</param>
''' <exception cref="System.ArgumentNullException">The collection parameter cannot be null.</exception>
Public Sub New(ByVal collection As IEnumerable(Of T))
MyBase.New(collection)
End Sub
''' <summary>
''' Adds the elements of the specified collection to the end of the ObservableCollection(Of T).
''' </summary>
Public Sub AddRange(ByVal collection As IEnumerable(Of T))
Dim ce As New NotifyCollectionChangingEventArgs(Of T)(NotifyCollectionChangedAction.Add, collection)
OnCollectionChanging(ce)
If ce.Cancel Then Exit Sub
Dim index = Items.Count - 1
For Each i In collection
Items.Add(i)
Next
OnCollectionChanged(New NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Add, collection, index))
End Sub
''' <summary>
''' Inserts the collection at specified index.
''' </summary>
Public Sub InsertRange(ByVal index As Integer, ByVal Collection As IEnumerable(Of T))
Dim ce As New NotifyCollectionChangingEventArgs(Of T)(NotifyCollectionChangedAction.Add, Collection)
OnCollectionChanging(ce)
If ce.Cancel Then Exit Sub
For Each i In Collection
Items.Insert(index, i)
Next
OnCollectionChanged(New NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Reset))
End Sub
''' <summary>
''' Removes the first occurence of each item in the specified collection from ObservableCollection(Of T).
''' </summary>
Public Sub RemoveRange(ByVal collection As IEnumerable(Of T))
Dim ce As New NotifyCollectionChangingEventArgs(Of T)(NotifyCollectionChangedAction.Remove, collection)
OnCollectionChanging(ce)
If ce.Cancel Then Exit Sub
For Each i In collection
Items.Remove(i)
Next
OnCollectionChanged(New NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Reset))
End Sub
''' <summary>
''' Clears the current collection and replaces it with the specified item.
''' </summary>
Public Sub Replace(ByVal item As T)
ReplaceRange(New T() {item})
End Sub
''' <summary>
''' Clears the current collection and replaces it with the specified collection.
''' </summary>
Public Sub ReplaceRange(ByVal collection As IEnumerable(Of T))
Dim ce As New NotifyCollectionChangingEventArgs(Of T)(NotifyCollectionChangedAction.Replace, Items)
OnCollectionChanging(ce)
If ce.Cancel Then Exit Sub
Items.Clear()
For Each i In collection
Items.Add(i)
Next
OnCollectionChanged(New NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Reset))
End Sub
Protected Overrides Sub ClearItems()
Dim e As New NotifyCollectionChangingEventArgs(Of T)(NotifyCollectionChangedAction.Reset, Items)
OnCollectionChanging(e)
If e.Cancel Then Exit Sub
MyBase.ClearItems()
End Sub
Protected Overrides Sub InsertItem(ByVal index As Integer, ByVal item As T)
Dim ce As New NotifyCollectionChangingEventArgs(Of T)(NotifyCollectionChangedAction.Add, item)
OnCollectionChanging(ce)
If ce.Cancel Then Exit Sub
MyBase.InsertItem(index, item)
End Sub
Protected Overrides Sub MoveItem(ByVal oldIndex As Integer, ByVal newIndex As Integer)
Dim ce As New NotifyCollectionChangingEventArgs(Of T)()
OnCollectionChanging(ce)
If ce.Cancel Then Exit Sub
MyBase.MoveItem(oldIndex, newIndex)
End Sub
Protected Overrides Sub RemoveItem(ByVal index As Integer)
Dim ce As New NotifyCollectionChangingEventArgs(Of T)(NotifyCollectionChangedAction.Remove, Items(index))
OnCollectionChanging(ce)
If ce.Cancel Then Exit Sub
MyBase.RemoveItem(index)
End Sub
Protected Overrides Sub SetItem(ByVal index As Integer, ByVal item As T)
Dim ce As New NotifyCollectionChangingEventArgs(Of T)(NotifyCollectionChangedAction.Replace, Items(index))
OnCollectionChanging(ce)
If ce.Cancel Then Exit Sub
MyBase.SetItem(index, item)
End Sub
Protected Overrides Sub OnCollectionChanged(ByVal e As Specialized.NotifyCollectionChangedEventArgs)
If e.NewItems IsNot Nothing Then
For Each i As T In e.NewItems
If TypeOf i Is INotifyPropertyChanged Then AddHandler DirectCast(i, INotifyPropertyChanged).PropertyChanged, AddressOf Item_PropertyChanged
Next
End If
MyBase.OnCollectionChanged(e)
End Sub
Private Sub Item_PropertyChanged(ByVal sender As T, ByVal e As ComponentModel.PropertyChangedEventArgs)
OnCollectionChanged(New NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Reset, sender, IndexOf(sender)))
End Sub
Public Event CollectionChanging(ByVal sender As Object, ByVal e As NotifyCollectionChangingEventArgs(Of T)) Implements INotifyCollectionChanging(Of T).CollectionChanging
Protected Overridable Sub OnCollectionChanging(ByVal e As NotifyCollectionChangingEventArgs(Of T))
RaiseEvent CollectionChanging(Me, e)
End Sub
End Class
Public Interface INotifyCollectionChanging(Of T)
Event CollectionChanging(ByVal sender As Object, ByVal e As NotifyCollectionChangingEventArgs(Of T))
End Interface
Public Class NotifyCollectionChangingEventArgs(Of T) : Inherits CancelEventArgs
Public Sub New()
m_Action = NotifyCollectionChangedAction.Move
m_Items = New T() {}
End Sub
Public Sub New(ByVal action As NotifyCollectionChangedAction, ByVal item As T)
m_Action = action
m_Items = New T() {item}
End Sub
Public Sub New(ByVal action As NotifyCollectionChangedAction, ByVal items As IEnumerable(Of T))
m_Action = action
m_Items = items
End Sub
Private m_Action As NotifyCollectionChangedAction
Public ReadOnly Property Action() As NotifyCollectionChangedAction
Get
Return m_Action
End Get
End Property
Private m_Items As IList
Public ReadOnly Property Items() As IEnumerable(Of T)
Get
Return m_Items
End Get
End Property
End Class
Я думаю, что AddRange лучше реализована так:
public void AddRange(IEnumerable<T> collection)
{
foreach (var i in collection) Items.Add(i);
OnCollectionChanged(
new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Reset));
}
Сохраняет копию списка. Кроме того, если вы хотите выполнить микрооптимизацию, вы можете делать добавление до N элементов, и если более N элементов, в которые добавлено, делает reset.
Подтверждение необходимости вызовов OnPropertyChanged("Count") и OnPropertyChanged("Item[]") для того, чтобы вести себя согласно ObservableCollection. Заметьте, что я не знаю, каковы последствия, если вы не беспокоитесь!
Вот тестовый метод, который показывает, что для каждого добавления в обычной наблюдаемой коллекции есть два события PropertyChange. Один для "Count" и один для "Item[]".
[TestMethod]
public void TestAddSinglesInOldObsevableCollection()
{
int colChangedEvents = 0;
int propChangedEvents = 0;
var collection = new ObservableCollection<object>();
collection.CollectionChanged += (sender, e) => { colChangedEvents++; };
(collection as INotifyPropertyChanged).PropertyChanged += (sender, e) => { propChangedEvents++; };
collection.Add(new object());
collection.Add(new object());
collection.Add(new object());
Assert.AreEqual(3, colChangedEvents);
Assert.AreEqual(6, propChangedEvents);
}
@Shimmy, замените стандарт для своей коллекции и измените на диапазон добавления, и вы получите нулевой PropertyChanges. Обратите внимание, что изменение коллекции отлично работает, но не делает то, что делает ObservableCollection. Итак, тест для коллекции shimmy выглядит следующим образом:
[TestMethod]
public void TestShimmyAddRange()
{
int colChangedEvents = 0;
int propChangedEvents = 0;
var collection = new ShimmyObservableCollection<object>();
collection.CollectionChanged += (sender, e) => { colChangedEvents++; };
(collection as INotifyPropertyChanged).PropertyChanged += (sender, e) => { propChangedEvents++; };
collection.AddRange(new[]{
new object(), new object(), new object(), new object()}); //4 objects at once
Assert.AreEqual(1, colChangedEvents); //great, just one!
Assert.AreEqual(2, propChangedEvents); //fails, no events :(
}
FYI - это код из InsertItem (также называемый Add) из ObservableCollection:
protected override void InsertItem(int index, T item)
{
base.CheckReentrancy();
base.InsertItem(index, item);
base.OnPropertyChanged("Count");
base.OnPropertyChanged("Item[]");
base.OnCollectionChanged(NotifyCollectionChangedAction.Add, item, index);
}
Вам нужно быть осторожным, привязывая пользовательский интерфейс к вашей пользовательской коллекции. Класс DefaultViewView поддерживает только одно уведомление о элементах.
Сводный потомок С#.
Дополнительная информация: http://blogs.msdn.com/b/nathannesbit/archive/2009/04/20/addrange-and-observablecollection.aspx
public sealed class ObservableCollectionEx<T> : ObservableCollection<T>
{
#region Ctor
public ObservableCollectionEx()
{
}
public ObservableCollectionEx(List<T> list) : base(list)
{
}
public ObservableCollectionEx(IEnumerable<T> collection) : base(collection)
{
}
#endregion
/// <summary>
/// Adds the elements of the specified collection to the end of the ObservableCollection(Of T).
/// </summary>
public void AddRange(
IEnumerable<T> itemsToAdd,
ECollectionChangeNotificationMode notificationMode = ECollectionChangeNotificationMode.Add)
{
if (itemsToAdd == null)
{
throw new ArgumentNullException("itemsToAdd");
}
CheckReentrancy();
if (notificationMode == ECollectionChangeNotificationMode.Reset)
{
foreach (var i in itemsToAdd)
{
Items.Add(i);
}
OnPropertyChanged(new PropertyChangedEventArgs("Count"));
OnPropertyChanged(new PropertyChangedEventArgs("Item[]"));
OnCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Reset));
return;
}
int startIndex = Count;
var changedItems = itemsToAdd is List<T> ? (List<T>) itemsToAdd : new List<T>(itemsToAdd);
foreach (var i in changedItems)
{
Items.Add(i);
}
OnPropertyChanged(new PropertyChangedEventArgs("Count"));
OnPropertyChanged(new PropertyChangedEventArgs("Item[]"));
OnCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Add, changedItems, startIndex));
}
public enum ECollectionChangeNotificationMode
{
/// <summary>
/// Notifies that only a portion of data was changed and supplies the changed items (not supported by some elements,
/// like CollectionView class).
/// </summary>
Add,
/// <summary>
/// Notifies that the entire collection was changed, does not supply the changed items (may be inneficient with large
/// collections as requires the full update even if a small portion of items was added).
/// </summary>
Reset
}
}
Да, добавление собственной коллекции Custom Observable Collection будет достаточно справедливым. Не забудьте поднять соответствующие события, независимо от того, используется ли это пользовательский интерфейс на данный момент или нет;) Вам нужно будет повысить уведомление об изменении свойства для свойства "Item []" (требуется со стороны WPF и связанных элементов управления), а также NotifyCollectionChangedEventArgs с добавленным набором элементов (ваш диапазон). Я делал такие вещи (а также поддержку сортировки и некоторые другие вещи) и не испытывал проблем как с представлениями, так и с кодами за слоями.
Так как в ObservableCollection может быть несколько операций, например, сначала очистить, а затем ДобавитьRange, а затем вставить элемент "Все" для ComboBox, я закончил следующее решение:
public static class LinqExtensions
{
public static ICollection<T> AddRange<T>(this ICollection<T> source, IEnumerable<T> addSource)
{
foreach(T item in addSource)
{
source.Add(item);
}
return source;
}
}
public class ExtendedObservableCollection<T>: ObservableCollection<T>
{
public void Execute(Action<IList<T>> itemsAction)
{
itemsAction(Items);
OnCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Reset));
}
}
И пример того, как его использовать:
MyDogs.Execute(items =>
{
items.Clear();
items.AddRange(Context.Dogs);
items.Insert(0, new Dog { Id = 0, Name = "All Dogs" });
});
Уведомление Reset будет вызываться только один раз после того, как Execute завершит обработку основного списка.
ObservableRangeCollection должен пройти тест, например
[Test]
public void TestAddRangeWhileBoundToListCollectionView()
{
int collectionChangedEventsCounter = 0;
int propertyChangedEventsCounter = 0;
var collection = new ObservableRangeCollection<object>();
collection.CollectionChanged += (sender, e) => { collectionChangedEventsCounter++; };
(collection as INotifyPropertyChanged).PropertyChanged += (sender, e) => { propertyChangedEventsCounter++; };
var list = new ListCollectionView(collection);
collection.AddRange(new[] { new object(), new object(), new object(), new object() });
Assert.AreEqual(4, collection.Count);
Assert.AreEqual(1, collectionChangedEventsCounter);
Assert.AreEqual(2, propertyChangedEventsCounter);
}
в противном случае получим
System.NotSupportedException : Range actions are not supported.
при использовании с элементом управления.
Я не вижу идеального решения, но NotifyCollectionChangedAction.Reset вместо Add/Remove частично решает проблему. См. http://blogs.msdn.com/b/nathannesbit/archive/2009/04/20/addrange-and-observablecollection.aspx, как было сказано net_prog
Здесь приведена модификация принятого ответа для обеспечения большей функциональности.
RangeCollection.cs:
public class RangeCollection<T> : ObservableCollection<T>
{
#region Members
/// <summary>
/// Occurs when a single item is added.
/// </summary>
public event EventHandler<ItemAddedEventArgs<T>> ItemAdded;
/// <summary>
/// Occurs when a single item is inserted.
/// </summary>
public event EventHandler<ItemInsertedEventArgs<T>> ItemInserted;
/// <summary>
/// Occurs when a single item is removed.
/// </summary>
public event EventHandler<ItemRemovedEventArgs<T>> ItemRemoved;
/// <summary>
/// Occurs when a single item is replaced.
/// </summary>
public event EventHandler<ItemReplacedEventArgs<T>> ItemReplaced;
/// <summary>
/// Occurs when items are added to this.
/// </summary>
public event EventHandler<ItemsAddedEventArgs<T>> ItemsAdded;
/// <summary>
/// Occurs when items are removed from this.
/// </summary>
public event EventHandler<ItemsRemovedEventArgs<T>> ItemsRemoved;
/// <summary>
/// Occurs when items are replaced within this.
/// </summary>
public event EventHandler<ItemsReplacedEventArgs<T>> ItemsReplaced;
/// <summary>
/// Occurs when entire collection is cleared.
/// </summary>
public event EventHandler<ItemsClearedEventArgs<T>> ItemsCleared;
/// <summary>
/// Occurs when entire collection is replaced.
/// </summary>
public event EventHandler<CollectionReplacedEventArgs<T>> CollectionReplaced;
#endregion
#region Helper Methods
/// <summary>
/// Throws exception if any of the specified objects are null.
/// </summary>
private void Check(params T[] Items)
{
foreach (T Item in Items)
{
if (Item == null)
{
throw new ArgumentNullException("Item cannot be null.");
}
}
}
private void Check(IEnumerable<T> Items)
{
if (Items == null) throw new ArgumentNullException("Items cannot be null.");
}
private void Check(IEnumerable<IEnumerable<T>> Items)
{
if (Items == null) throw new ArgumentNullException("Items cannot be null.");
}
private void RaiseChanged(NotifyCollectionChangedAction Action)
{
this.OnPropertyChanged(new PropertyChangedEventArgs("Count"));
this.OnPropertyChanged(new PropertyChangedEventArgs("Item[]"));
this.OnCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Reset));
}
#endregion
#region Bulk Methods
/// <summary>
/// Adds the elements of the specified collection to the end of this.
/// </summary>
public void AddRange(IEnumerable<T> NewItems)
{
this.Check(NewItems);
foreach (var i in NewItems) this.Items.Add(i);
this.RaiseChanged(NotifyCollectionChangedAction.Reset);
this.OnItemsAdded(new ItemsAddedEventArgs<T>(NewItems));
}
/// <summary>
/// Adds variable IEnumerable<T> to this.
/// </summary>
/// <param name="List"></param>
public void AddRange(params IEnumerable<T>[] NewItems)
{
this.Check(NewItems);
foreach (IEnumerable<T> Items in NewItems) foreach (T Item in Items) this.Items.Add(Item);
this.RaiseChanged(NotifyCollectionChangedAction.Reset);
//TO-DO: Raise OnItemsAdded with combined IEnumerable<T>.
}
/// <summary>
/// Removes the first occurence of each item in the specified collection.
/// </summary>
public void Remove(IEnumerable<T> OldItems)
{
this.Check(OldItems);
foreach (var i in OldItems) Items.Remove(i);
this.RaiseChanged(NotifyCollectionChangedAction.Reset);
OnItemsRemoved(new ItemsRemovedEventArgs<T>(OldItems));
}
/// <summary>
/// Removes all occurences of each item in the specified collection.
/// </summary>
/// <param name="itemsToRemove"></param>
public void RemoveAll(IEnumerable<T> OldItems)
{
this.Check(OldItems);
var set = new HashSet<T>(OldItems);
var list = this as List<T>;
int i = 0;
while (i < this.Count) if (set.Contains(this[i])) this.RemoveAt(i); else i++;
this.RaiseChanged(NotifyCollectionChangedAction.Reset);
OnItemsRemoved(new ItemsRemovedEventArgs<T>(OldItems));
}
/// <summary>
/// Replaces all occurences of a single item with specified item.
/// </summary>
public void ReplaceAll(T Old, T New)
{
this.Check(Old, New);
this.Replace(Old, New, false);
this.RaiseChanged(NotifyCollectionChangedAction.Reset);
this.OnItemReplaced(new ItemReplacedEventArgs<T>(Old, New));
}
/// <summary>
/// Clears this and adds specified collection.
/// </summary>
public void ReplaceCollection(IEnumerable<T> NewItems, bool SupressEvent = false)
{
this.Check(NewItems);
IEnumerable<T> OldItems = new List<T>(this.Items);
this.Items.Clear();
foreach (T Item in NewItems) this.Items.Add(Item);
this.RaiseChanged(NotifyCollectionChangedAction.Reset);
this.OnReplaced(new CollectionReplacedEventArgs<T>(OldItems, NewItems));
}
private void Replace(T Old, T New, bool BreakFirst)
{
List<T> Cloned = new List<T>(this.Items);
int i = 0;
foreach (T Item in Cloned)
{
if (Item.Equals(Old))
{
this.Items.Remove(Item);
this.Items.Insert(i, New);
if (BreakFirst) break;
}
i++;
}
}
/// <summary>
/// Replaces the first occurence of a single item with specified item.
/// </summary>
public void Replace(T Old, T New)
{
this.Check(Old, New);
this.Replace(Old, New, true);
this.RaiseChanged(NotifyCollectionChangedAction.Reset);
this.OnItemReplaced(new ItemReplacedEventArgs<T>(Old, New));
}
#endregion
#region New Methods
/// <summary>
/// Removes a single item.
/// </summary>
/// <param name="Item"></param>
public new void Remove(T Item)
{
this.Check(Item);
base.Remove(Item);
OnItemRemoved(new ItemRemovedEventArgs<T>(Item));
}
/// <summary>
/// Removes a single item at specified index.
/// </summary>
/// <param name="i"></param>
public new void RemoveAt(int i)
{
T OldItem = this.Items[i]; //This will throw first if null
base.RemoveAt(i);
OnItemRemoved(new ItemRemovedEventArgs<T>(OldItem));
}
/// <summary>
/// Clears this.
/// </summary>
public new void Clear()
{
IEnumerable<T> OldItems = new List<T>(this.Items);
this.Items.Clear();
this.RaiseChanged(NotifyCollectionChangedAction.Reset);
this.OnCleared(new ItemsClearedEventArgs<T>(OldItems));
}
/// <summary>
/// Adds a single item to end of this.
/// </summary>
/// <param name="t"></param>
public new void Add(T Item)
{
this.Check(Item);
base.Add(Item);
this.OnItemAdded(new ItemAddedEventArgs<T>(Item));
}
/// <summary>
/// Inserts a single item at specified index.
/// </summary>
/// <param name="i"></param>
/// <param name="t"></param>
public new void Insert(int i, T Item)
{
this.Check(Item);
base.Insert(i, Item);
this.OnItemInserted(new ItemInsertedEventArgs<T>(Item, i));
}
/// <summary>
/// Returns list of T.ToString().
/// </summary>
/// <returns></returns>
public new IEnumerable<string> ToString()
{
foreach (T Item in this) yield return Item.ToString();
}
#endregion
#region Event Methods
private void OnItemAdded(ItemAddedEventArgs<T> i)
{
if (this.ItemAdded != null) this.ItemAdded(this, new ItemAddedEventArgs<T>(i.NewItem));
}
private void OnItemInserted(ItemInsertedEventArgs<T> i)
{
if (this.ItemInserted != null) this.ItemInserted(this, new ItemInsertedEventArgs<T>(i.NewItem, i.Index));
}
private void OnItemRemoved(ItemRemovedEventArgs<T> i)
{
if (this.ItemRemoved != null) this.ItemRemoved(this, new ItemRemovedEventArgs<T>(i.OldItem));
}
private void OnItemReplaced(ItemReplacedEventArgs<T> i)
{
if (this.ItemReplaced != null) this.ItemReplaced(this, new ItemReplacedEventArgs<T>(i.OldItem, i.NewItem));
}
private void OnItemsAdded(ItemsAddedEventArgs<T> i)
{
if (this.ItemsAdded != null) this.ItemsAdded(this, new ItemsAddedEventArgs<T>(i.NewItems));
}
private void OnItemsRemoved(ItemsRemovedEventArgs<T> i)
{
if (this.ItemsRemoved != null) this.ItemsRemoved(this, new ItemsRemovedEventArgs<T>(i.OldItems));
}
private void OnItemsReplaced(ItemsReplacedEventArgs<T> i)
{
if (this.ItemsReplaced != null) this.ItemsReplaced(this, new ItemsReplacedEventArgs<T>(i.OldItems, i.NewItems));
}
private void OnCleared(ItemsClearedEventArgs<T> i)
{
if (this.ItemsCleared != null) this.ItemsCleared(this, new ItemsClearedEventArgs<T>(i.OldItems));
}
private void OnReplaced(CollectionReplacedEventArgs<T> i)
{
if (this.CollectionReplaced != null) this.CollectionReplaced(this, new CollectionReplacedEventArgs<T>(i.OldItems, i.NewItems));
}
#endregion
#region RangeCollection
/// <summary>
/// Initializes a new instance.
/// </summary>
public RangeCollection() : base() { }
/// <summary>
/// Initializes a new instance from specified enumerable.
/// </summary>
public RangeCollection(IEnumerable<T> Collection) : base(Collection) { }
/// <summary>
/// Initializes a new instance from specified list.
/// </summary>
public RangeCollection(List<T> List) : base(List) { }
/// <summary>
/// Initializes a new instance with variable T.
/// </summary>
public RangeCollection(params T[] Items) : base()
{
this.AddRange(Items);
}
/// <summary>
/// Initializes a new instance with variable enumerable.
/// </summary>
public RangeCollection(params IEnumerable<T>[] Items) : base()
{
this.AddRange(Items);
}
#endregion
}
Классы событий:
public class CollectionReplacedEventArgs<T> : ReplacedEventArgs<T>
{
public CollectionReplacedEventArgs(IEnumerable<T> Old, IEnumerable<T> New) : base(Old, New) { }
}
public class ItemAddedEventArgs<T> : EventArgs
{
public T NewItem;
public ItemAddedEventArgs(T t)
{
this.NewItem = t;
}
}
public class ItemInsertedEventArgs<T> : EventArgs
{
public int Index;
public T NewItem;
public ItemInsertedEventArgs(T t, int i)
{
this.NewItem = t;
this.Index = i;
}
}
public class ItemRemovedEventArgs<T> : EventArgs
{
public T OldItem;
public ItemRemovedEventArgs(T t)
{
this.OldItem = t;
}
}
public class ItemReplacedEventArgs<T> : EventArgs
{
public T OldItem;
public T NewItem;
public ItemReplacedEventArgs(T Old, T New)
{
this.OldItem = Old;
this.NewItem = New;
}
}
public class ItemsAddedEventArgs<T> : EventArgs
{
public IEnumerable<T> NewItems;
public ItemsAddedEventArgs(IEnumerable<T> t)
{
this.NewItems = t;
}
}
public class ItemsClearedEventArgs<T> : RemovedEventArgs<T>
{
public ItemsClearedEventArgs(IEnumerable<T> Old) : base(Old) { }
}
public class ItemsRemovedEventArgs<T> : RemovedEventArgs<T>
{
public ItemsRemovedEventArgs(IEnumerable<T> Old) : base(Old) { }
}
public class ItemsReplacedEventArgs<T> : ReplacedEventArgs<T>
{
public ItemsReplacedEventArgs(IEnumerable<T> Old, IEnumerable<T> New) : base(Old, New) { }
}
public class RemovedEventArgs<T> : EventArgs
{
public IEnumerable<T> OldItems;
public RemovedEventArgs(IEnumerable<T> Old)
{
this.OldItems = Old;
}
}
public class ReplacedEventArgs<T> : EventArgs
{
public IEnumerable<T> OldItems;
public IEnumerable<T> NewItems;
public ReplacedEventArgs(IEnumerable<T> Old, IEnumerable<T> New)
{
this.OldItems = Old;
this.NewItems = New;
}
}
Примечание. Я не вручную подбрасывал OnCollectionChanged в базовых методах, потому что возможно создать CollectionChangedEventArgs только с помощью действия Reset. Если вы попытаетесь поднять OnCollectionChanged с помощью Reset для изменения одного элемента, ваш элемент управления будет мерцать, чего вы хотите избежать.
Вы также можете использовать этот код для расширения ObservableCollection:
public static class ObservableCollectionExtend
{
public static void AddRange<TSource>(this ObservableCollection<TSource> source, IEnumerable<TSource> items)
{
foreach (var item in items)
{
source.Add(item);
}
}
}
Тогда вам не нужно менять класс в существующем коде.