/// <summary>
/// This API supports the Entity Framework Core infrastructure and is not intended to be used
/// directly from your code. This API may change or be removed in future releases.
/// </summary>
public virtual void NavigationCollectionChanged(
InternalEntityEntry entry,
INavigation navigation,
IEnumerable <object> added,
IEnumerable <object> removed)
{
if (_inFixup)
{
return;
}
var foreignKey = navigation.ForeignKey;
var stateManager = entry.StateManager;
var inverse = navigation.FindInverse();
var targetEntityType = navigation.GetTargetType();
foreach (var oldValue in removed)
{
var oldTargetEntry = stateManager.TryGetEntry(oldValue, targetEntityType);
if (oldTargetEntry != null &&
oldTargetEntry.EntityState != EntityState.Detached)
{
try
{
_inFixup = true;
// Null FKs and navigations of dependents that have been removed, unless they
// have already been changed.
ConditionallyNullForeignKeyProperties(oldTargetEntry, entry, foreignKey);
if (inverse != null &&
ReferenceEquals(oldTargetEntry[inverse], entry.Entity) &&
oldTargetEntry.StateManager.TryGetEntry(oldTargetEntry.Entity, targetEntityType) != null)
{
SetNavigation(oldTargetEntry, inverse, null);
}
entry.RemoveFromCollectionSnapshot(navigation, oldValue);
}
finally
{
_inFixup = false;
}
}
}
foreach (var newValue in added)
{
var newTargetEntry = targetEntityType.HasDefiningNavigation()
? stateManager.GetOrCreateEntry(newValue, targetEntityType)
: stateManager.GetOrCreateEntry(newValue);
if (newTargetEntry.EntityState != EntityState.Detached)
{
try
{
_inFixup = true;
// For a dependent added to the collection, remove it from the collection of
// the principal entity that it was previously part of
var oldPrincipalEntry = stateManager.GetPrincipalUsingRelationshipSnapshot(newTargetEntry, foreignKey);
if (oldPrincipalEntry != null &&
oldPrincipalEntry != entry)
{
RemoveFromCollection(oldPrincipalEntry, navigation, newTargetEntry);
}
// Set the FK properties on added dependents to match this principal
SetForeignKeyProperties(newTargetEntry, entry, foreignKey, setModified: true);
// Set the inverse navigation to point to this principal
SetNavigation(newTargetEntry, inverse, entry);
}
finally
{
_inFixup = false;
}
}
else
{
stateManager.RecordReferencedUntrackedEntity(newValue, navigation, entry);
_attacher.AttachGraph(newTargetEntry, EntityState.Added, forceStateWhenUnknownKey: false);
}
entry.AddToCollectionSnapshot(navigation, newValue);
}
}
private void DetectNavigationChange(InternalEntityEntry entry, INavigation navigation)
{
var snapshotValue = entry.GetRelationshipSnapshotValue(navigation);
var currentValue = entry[navigation];
var stateManager = entry.StateManager;
var added = new HashSet <object>(ReferenceEqualityComparer.Instance);
if (navigation.IsCollection())
{
var snapshotCollection = (IEnumerable)snapshotValue;
var currentCollection = (IEnumerable)currentValue;
var removed = new HashSet <object>(ReferenceEqualityComparer.Instance);
if (snapshotCollection != null)
{
foreach (var entity in snapshotCollection)
{
removed.Add(entity);
}
}
if (currentCollection != null)
{
foreach (var entity in currentCollection)
{
if (!removed.Remove(entity))
{
added.Add(entity);
}
}
}
if (added.Any() ||
removed.Any())
{
stateManager.Notify.NavigationCollectionChanged(entry, navigation, added, removed);
foreach (var addedEntity in added)
{
entry.AddToCollectionSnapshot(navigation, addedEntity);
}
foreach (var removedEntity in removed)
{
entry.RemoveFromCollectionSnapshot(navigation, removedEntity);
}
}
}
else if (!ReferenceEquals(currentValue, snapshotValue))
{
stateManager.Notify.NavigationReferenceChanged(entry, navigation, snapshotValue, currentValue);
if (currentValue != null)
{
added.Add(currentValue);
}
entry.SetRelationshipSnapshotValue(navigation, currentValue);
}
foreach (var addedEntity in added)
{
var addedEntry = stateManager.GetOrCreateEntry(addedEntity);
if (addedEntry.EntityState == EntityState.Detached)
{
_attacher.AttachGraph(addedEntry, EntityState.Added);
}
}
}