/// <summary>
/// Construtor padrão.
/// </summary>
/// <param name="source">Relação da coleção de origem dos dados.</param>
/// <param name="comparer">Comparador que será utilizado para ordenar os itens.</param>
public SortableObservableCollection(IObservableCollection <T> source, IComparer <T> comparer)
{
source.Require("source").NotNull();
comparer.Require("comparer").NotNull();
_source = source;
_comparer = comparer;
_comparerPropertiesContainer = comparer as IPropertiesContainer;
_source.CollectionChanged += SourceCollectionChanged;
_indexes = new BaseObservableCollection <int>();
for (var i = 0; i < _source.Count; i++)
{
_indexes.Add(i);
}
foreach (var i in _source)
{
RegisterItem(i);
}
CalculateIndexes();
}
/// <summary>
/// Método acionado quando a coleção de origem for alterada.
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
private void SourceCollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
{
if (e.Action == NotifyCollectionChangedAction.Add)
{
for (var i = 0; i < e.NewItems.Count; i++)
{
var item = (T)e.NewItems[i];
var inserted = false;
for (var j = 0; j < _indexes.Count; j++)
{
if (_comparer.Compare(_source[_indexes[j]], item) > 0)
{
_indexes.Insert(j, e.NewStartingIndex + i);
RegisterItem(item);
inserted = true;
break;
}
}
if (!inserted)
{
_indexes.Add(e.NewStartingIndex + i);
}
}
}
else if (e.Action == NotifyCollectionChangedAction.Move)
{
for (var i = 0; i < e.NewItems.Count; i++)
{
var newIndex = -1;
var oldIndex = -1;
for (var j = 0; (newIndex < 0 || oldIndex < 0) && j < _indexes.Count; j++)
{
if (newIndex < 0 && _indexes[j] == e.NewStartingIndex + i)
{
newIndex = j;
}
else if (oldIndex < 0 && _indexes[j] == e.OldStartingIndex + i)
{
oldIndex = j;
}
}
if (newIndex >= 0 && oldIndex >= 0)
{
var aux = _indexes[newIndex];
_indexes[newIndex] = _indexes[oldIndex];
_indexes[oldIndex] = aux;
}
}
}
else if (e.Action == NotifyCollectionChangedAction.Remove)
{
for (var i = 0; i < e.OldItems.Count; i++)
{
for (var j = 0; j < _indexes.Count; j++)
{
if (_indexes[j] == e.OldStartingIndex + i)
{
UnregisterItem((T)e.OldItems[i]);
_indexes.CollectionChanged -= IndexesCollectionChanged;
_indexes.Clear();
for (var x = 0; x < _source.Count; x++)
{
_indexes.Add(x);
}
try
{
CalculateIndexesWithoutNotifyChanges();
}
finally
{
_indexes.CollectionChanged += IndexesCollectionChanged;
}
if (CollectionChanged != null)
{
CollectionChanged(this, new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Remove, e.OldItems[i], j));
}
break;
}
}
}
}
else if (e.Action == NotifyCollectionChangedAction.Replace)
{
CalculateIndexes();
}
else if (e.Action == NotifyCollectionChangedAction.Reset)
{
try
{
_indexes.CollectionChanged -= IndexesCollectionChanged;
foreach (var item in _source)
{
UnregisterItem(item);
}
for (var i = 0; i < _source.Count; i++)
{
_indexes.Add(i);
}
}
finally
{
_indexes.CollectionChanged += IndexesCollectionChanged;
}
CalculateIndexes();
}
}
