/// <summary>
/// Called by the <see cref="ObservableCollection{T}" /> base class when the collection changes.
/// This method looks at the change made to the collection and reflects those changes in the
/// state manager.
/// </summary>
/// <param name="e">
/// The <see cref="System.Collections.Specialized.NotifyCollectionChangedEventArgs" /> instance containing the event data.
/// </param>
protected override void OnCollectionChanged(NotifyCollectionChangedEventArgs e)
{
Debug.Assert(
e.Action != NotifyCollectionChangedAction.Reset,
"Should not get Reset event from our derived implementation of ObservableCollection.");
// Avoid recursively reacting to changes made to this list while already processing state manager changes.
// That is, the ObservableCollection only changed because we made a change based on the state manager.
// We therefore don't want to try to repeat that change in the state manager.
if (!_inStateManagerChanged &&
_internalContext != null)
{
if (e.Action == NotifyCollectionChangedAction.Remove ||
e.Action == NotifyCollectionChangedAction.Replace)
{
foreach (TEntity entity in e.OldItems)
{
_internalContext.Set <TEntity>().Remove(entity);
}
}
if (e.Action == NotifyCollectionChangedAction.Add ||
e.Action == NotifyCollectionChangedAction.Replace)
{
foreach (TEntity entity in e.NewItems)
{
// For something that is already in the state manager as Unchanged or Modified we don't try
// to Add it again since doing so would change its state to Added, which is probably not what
// was wanted in this case.
if (!_internalContext.EntityInContextAndNotDeleted(entity))
{
_internalContext.Set <TEntity>().Add(entity);
}
}
}
}
base.OnCollectionChanged(e);
}