/// <summary>
/// Removes the specified element from a <see cref="IndexedCollection{T}"/>.
/// </summary>
/// <param name="item"> The element to remove. </param>
/// <returns>
/// true if the element is successfully found and removed; otherwise, false.
/// This method returns false if item is not found in the <see cref="IndexedCollection{T}"/>.
/// </returns>
/// <exception cref="ArgumentNullException"> <paramref name="item"/> is null. </exception>
public bool Remove(T item)
{
if (item == null)
{
throw new ArgumentNullException(nameof(item));
}
if (_storage.TryGetValue(item, out List <object> indexKeys))
{
for (int i = 0; i < _indexes.Count; i++)
{
IEqualityIndex <T> index = _indexes[i];
object lastKey = indexKeys[i];
index.Remove(lastKey, item);
}
_storage.Remove(item);
if (item is INotifyPropertyChanged observable)
{
observable.PropertyChanged -= OnPropertyChanged;
}
return(true);
}
else
{
return(false);
}
}
/// <exception cref="NotSupportedException" />
/// <exception cref="InvalidOperationException" />
private IEnumerable <T> FilterEquality(Expression memberExpression, Expression keyExpression)
{
string memberName = memberExpression.GetMemberName();
IEqualityIndex <T> index = _indexes.Find(i => i.MemberName == memberName);
if (index == null)
{
throw new InvalidOperationException($"There is no index for property '{memberName}'");
}
return(index.Filter(keyExpression.GetValue()));
}
private void IndexBy(IEqualityIndex <T> index)
{
foreach (var pair in _storage)
{
T item = pair.Key;
List <object> indexKeys = pair.Value;
object key = index.GetKey(item);
indexKeys.Add(key);
index.Add(key, item);
}
_indexes.Add(index);
}
private void OnPropertyChanged(object sender, PropertyChangedEventArgs e)
{
int pointer = _indexes.FindIndex(i => i.MemberName == e.PropertyName);
if (pointer != -1 && sender is T item &&
_storage.TryGetValue(item, out List <object> indexKeys))
{
IEqualityIndex <T> index = _indexes[pointer];
object currentKey = index.GetKey(item);
object lastKey = indexKeys[pointer];
indexKeys[pointer] = currentKey;
index.Remove(lastKey, item);
index.Add(currentKey, item);
}
}
private void AddOrUpdate(T item)
{
if (_storage.TryGetValue(item, out List <object> indexKeys))
{
for (int i = 0; i < _indexes.Count; i++)
{
IEqualityIndex <T> index = _indexes[i];
object currentKey = index.GetKey(item);
object lastKey = indexKeys[i];
if (!Equals(lastKey, currentKey))
{
indexKeys[i] = currentKey;
index.Remove(lastKey, item);
index.Add(currentKey, item);
}
}
}
else
{
indexKeys = new List <object>(_indexes.Count);
foreach (IEqualityIndex <T> index in _indexes)
{
object key = index.GetKey(item);
indexKeys.Add(key);
index.Add(key, item);
}
_storage.Add(item, indexKeys);
if (item is INotifyPropertyChanged observable)
{
observable.PropertyChanged += OnPropertyChanged;
}
}
}
