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using System.Collections.Generic;
using System.Collections.Specialized;
using System.ComponentModel;
using System.Linq;
using System.Linq.Expressions;
using System.Threading;
using System.Windows.Threading;
namespace System.Collections.ObjectModel
{
public class ObservableCollectionEx<T>
: IList<T>, IList
, INotifyCollectionChanged
, INotifyPropertyChanged
where T : INotifyPropertyChanged
{
#region Fields
private readonly IList<T> collection = new List<T>();
private readonly Dispatcher dispatcher;
private readonly ReaderWriterLock sync = new ReaderWriterLock();
private readonly List<T> _InternalList = new List<T>();
[NonSerialized]
private object _syncRoot;
#endregion
#region Constructors
public ObservableCollectionEx()
{
dispatcher = Dispatcher.CurrentDispatcher;
}
public ObservableCollectionEx(IEnumerable<T> createFrom)
: this()
{
Source = createFrom;
}
#endregion
#region Properties
#region Filter
private Func<T, bool> _Filter;
public Func<T, bool> Filter
{
get { return _Filter; }
set
{
//ignore if values are equal
if (value == _Filter) return;
_Filter = value;
ApplyFilter();
RaisePropertyChanged(() => Filter);
}
}
#endregion
#region Source
private IEnumerable<T> _Source;
public IEnumerable<T> Source
{
get
{
return _Source;
}
set
{
//ignore if values are equal
if (value == _Source) return;
if (_Source is INotifyCollectionChanged)
(_Source as INotifyCollectionChanged).CollectionChanged -= Source_CollectionChanged;
_Source = value;
InitFrom(_Source);
if (_Source is INotifyCollectionChanged)
(_Source as INotifyCollectionChanged).CollectionChanged += Source_CollectionChanged;
RaisePropertyChanged(() => Source);
}
}
#endregion
#endregion
#region Methods
public void Add(T item)
{
if (Thread.CurrentThread == dispatcher.Thread)
DoAdd(item);
else
dispatcher.BeginInvoke((Action)(() => DoAdd(item)));
}
private int DoAdd(T item)
{
sync.AcquireWriterLock(Timeout.Infinite);
var index = DoAddInternal(item, true);
sync.ReleaseWriterLock();
return index;
}
private int DoAddInternal(T item, bool attachMonitorChanges)
{
// Attach to PropertyChanged event for monitoring future properties' changes
if (attachMonitorChanges)
AttachPropertyChanged(item);
// Check if it should be here
if (!ShouldBeHere(item))
return -1;
// Add item to collection
var index = collection.Count;
collection.Add(item);
// Notify about collection's changes
RaisePropertyChanged(() => Count);
RaisePropertyChanged("Item[]");
RaiseCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Add, item, index));
return index;
}
public int Add(object item)
{
if (Thread.CurrentThread == dispatcher.Thread)
return DoAdd((T)item);
else
{
var op = dispatcher.BeginInvoke(new Func<T, int>(DoAdd), item);
if (op == null || op.Result == null)
return -1;
return (int)op.Result;
}
}
public bool Contains(object value)
{
return Contains((T) value);
}
public void Clear()
{
if (Thread.CurrentThread == dispatcher.Thread)
DoClear();
else
dispatcher.BeginInvoke((Action)(DoClear));
}
public int IndexOf(object value)
{
return IndexOf((T) value);
}
public void Insert(int index, object value)
{
Insert(index, (T)value);
}
public void Remove(object value)
{
Remove((T) value);
}
private void DoClear()
{
sync.AcquireWriterLock(Timeout.Infinite);
DoClearInternal();
sync.ReleaseWriterLock();
}
private void DoClearInternal()
{
// Detach from PropertyChanged events
foreach (var item in _InternalList.ToArray())
DetachPropertyChanged(item);
// Clear collection
collection.Clear();
// Notify about collection's changes
RaisePropertyChanged(() => Count);
RaisePropertyChanged("Item[]");
RaiseCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Reset));
}
public bool Contains(T item)
{
sync.AcquireReaderLock(Timeout.Infinite);
var result = ContainsInternal(item);
sync.ReleaseReaderLock();
return result;
}
private bool ContainsInternal(T item)
{
return collection.Contains(item);
}
public void CopyTo(T[] array, int arrayIndex)
{
sync.AcquireWriterLock(Timeout.Infinite);
collection.CopyTo(array, arrayIndex);
sync.ReleaseWriterLock();
}
public void CopyTo(Array array, int index)
{
sync.AcquireWriterLock(Timeout.Infinite);
for (var i = 0; i < collection.Count; i ++)
{
array.SetValue(collection[i], index + i);
}
sync.ReleaseWriterLock();
}
public int Count
{
get
{
sync.AcquireReaderLock(Timeout.Infinite);
var result = collection.Count;
sync.ReleaseReaderLock();
return result;
}
}
public object SyncRoot
{
get
{
if (_syncRoot == null)
{
var c = collection as ICollection;
if (c != null)
_syncRoot = c.SyncRoot;
else
Interlocked.CompareExchange<object>(ref _syncRoot, new object(), null);
}
return _syncRoot;
}
}
public bool IsSynchronized
{
get { return false; }
}
public bool IsReadOnly
{
get
{
return false;
}
}
public bool IsFixedSize
{
get { return false; }
}
public bool Remove(T item)
{
if (Thread.CurrentThread == dispatcher.Thread)
return DoRemove(item);
else
{
var op = dispatcher.BeginInvoke(new Func<T, bool>(DoRemove), item);
if (op == null || op.Result == null)
return false;
return (bool)op.Result;
}
}
private bool DoRemove(T item)
{
sync.AcquireWriterLock(Timeout.Infinite);
var result = DoRemoveInternal(item, true);
sync.ReleaseWriterLock();
return result;
}
private bool DoRemoveInternal(T item, bool detachMonitorChanges)
{
// Check if item is still at collection
var index = collection.IndexOf(item);
if (index == -1)
return false;
// Detach from PropertyChanged event
if (detachMonitorChanges)
DetachPropertyChanged(item);
// Remove item from collection
var result = collection.Remove(item);
// Notify about collection's changes
if (result)
{
RaisePropertyChanged(() => Count);
RaisePropertyChanged("Item[]");
RaiseCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Remove, item,
index));
}
return result;
}
public IEnumerator<T> GetEnumerator()
{
return collection.GetEnumerator();
}
System.Collections.IEnumerator System.Collections.IEnumerable.GetEnumerator()
{
return collection.GetEnumerator();
}
public int IndexOf(T item)
{
sync.AcquireReaderLock(Timeout.Infinite);
var result = collection.IndexOf(item);
sync.ReleaseReaderLock();
return result;
}
public void Insert(int index, T item)
{
if (Thread.CurrentThread == dispatcher.Thread)
DoInsert(index, item);
else
dispatcher.BeginInvoke((Action)(() => DoInsert(index, item)));
}
private void DoInsert(int index, T item)
{
sync.AcquireWriterLock(Timeout.Infinite);
// Attach to PropertyChanged event for monitoring future properties' changes
AttachPropertyChanged(item);
// Check if it should be here
if (!ShouldBeHere(item))
return;
// Insert item in collection
collection.Insert(index, item);
// Notify about collection's changes
RaisePropertyChanged(() => Count);
RaisePropertyChanged("Item[]");
RaiseCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Add, item, index));
sync.ReleaseWriterLock();
}
public void RemoveAt(int index)
{
if (Thread.CurrentThread == dispatcher.Thread)
DoRemoveAt(index);
else
dispatcher.BeginInvoke((Action)(() => DoRemoveAt(index)));
}
object IList.this[int index]
{
get { return this[index]; }
set { this[index] = (T)value; }
}
private void DoRemoveAt(int index)
{
sync.AcquireWriterLock(Timeout.Infinite);
if (collection.Count == 0 || collection.Count <= index)
{
sync.ReleaseWriterLock();
return;
}
var item = collection[index];
// Detach from PropertyChanged event
DetachPropertyChanged(item);
// Remove item from collection
collection.RemoveAt(index);
// Notify about collection's changes
RaisePropertyChanged(() => Count);
RaisePropertyChanged("Item[]");
RaiseCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Remove, item, index));
sync.ReleaseWriterLock();
}
public T this[int index]
{
get
{
sync.AcquireReaderLock(Timeout.Infinite);
var result = collection[index];
sync.ReleaseReaderLock();
return result;
}
set
{
sync.AcquireWriterLock(Timeout.Infinite);
if (collection.Count == 0 || collection.Count <= index)
{
sync.ReleaseWriterLock();
return;
}
var oldItem = collection[index];
DetachPropertyChanged(oldItem);
AttachPropertyChanged(value);
if (ShouldBeHere(value))
{
collection[index] = value;
// Notify about collection's changes
RaisePropertyChanged("Item[]");
RaiseCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Replace, value, oldItem, index));
}
else
{
//
// Remove current item from collection
//
// Detach from PropertyChanged event
DetachPropertyChanged(oldItem);
// Remove item from collection
collection.RemoveAt(index);
// Notify about collection's changes
RaisePropertyChanged(() => Count);
RaisePropertyChanged("Item[]");
RaiseCollectionChanged(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Remove, oldItem, index));
}
sync.ReleaseWriterLock();
}
}
#region Internal methods
private void AttachPropertyChanged(T item)
{
_InternalList.Add(item);
if (item is INotifyPropertyChanged)
{
(item as INotifyPropertyChanged).PropertyChanged += Item_PropertyChanged;
(item as INotifyPropertyChanged).PropertyChanged += EntityViewModelPropertyChanged;
}
}
private void DetachPropertyChanged(T item)
{
_InternalList.Remove(item);
if (item is INotifyPropertyChanged)
{
(item as INotifyPropertyChanged).PropertyChanged -= Item_PropertyChanged;
(item as INotifyPropertyChanged).PropertyChanged -= EntityViewModelPropertyChanged;
}
}
private void Item_PropertyChanged(object sender, PropertyChangedEventArgs e)
{
sync.AcquireWriterLock(Timeout.Infinite);
var item = (T) sender;
var containsAfter = ApplyFilter(item);
if (containsAfter)
if (ItemPropertyChanged != null)
ItemPropertyChanged(sender, e);
sync.ReleaseWriterLock();
}
private bool ApplyFilter(T item)
{
var contains = ContainsInternal(item);
var containsAfter = contains;
if (ShouldBeHere(item))
{
if (!contains)
{
DoAddInternal(item, false);
containsAfter = true;
}
}
else
{
if (contains)
{
DoRemoveInternal(item, false);
containsAfter = false;
}
}
return containsAfter;
}
private bool ShouldBeHere(T item)
{
return (Filter == null) || Filter(item);
}
private void RaisePropertyChanged<TSource>(Expression<Func<TSource>> propertyExpression)
{
var propertyName = ((MemberExpression)propertyExpression.Body).Member.Name;
RaisePropertyChanged(propertyName);
}
private void RaisePropertyChanged(string propertyName)
{
if (PropertyChanged != null)
PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
}
private void InitFrom(IEnumerable<T> source)
{
if (source == null)
{
Clear();
return;
}
sync.AcquireWriterLock(Timeout.Infinite);
foreach (var item in source)
{
DoAddInternal(item, true);
}
sync.ReleaseWriterLock();
}
private void RaiseCollectionChanged(NotifyCollectionChangedEventArgs e)
{
if (CollectionChanged != null)
CollectionChanged(this, e);
}
public void ApplyFilter()
{
sync.AcquireWriterLock(Timeout.Infinite);
foreach (var item in _InternalList)
{
ApplyFilter(item);
}
sync.ReleaseWriterLock();
}
#endregion
#endregion
#region Events
public event NotifyCollectionChangedEventHandler CollectionChanged;
public event PropertyChangedEventHandler ItemPropertyChanged;
public event PropertyChangedEventHandler PropertyChanged;
#endregion
#region Event handlers
void Source_CollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
{
sync.AcquireWriterLock(Timeout.Infinite);
if (e.OldItems != null)
{
foreach (var oldItem in e.OldItems.OfType<T>())
{
DoRemoveInternal(oldItem, true);
}
}
if (e.NewItems != null)
{
foreach (var newItem in e.NewItems.OfType<T>())
{
DoAddInternal(newItem, true);
}
}
sync.ReleaseWriterLock();
}
void EntityViewModelPropertyChanged(object sender, PropertyChangedEventArgs e)
{
NotifyCollectionChangedEventArgs args = new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Reset);
this.CollectionChanged(sender, args);
}
#endregion
}
} |
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