public async Task UpdateChildren <T, TProperty>(T parent, Expression <Func <T, IEnumerable <TProperty> > > childSelector, IEqualityComparer <TProperty> comparer = null) where T : BaseEntity where TProperty : BaseEntity
{
var stateManager = ((IObjectContextAdapter)this).ObjectContext.ObjectStateManager;
var currentChildren = childSelector.Invoke(parent) ?? Enumerable.Empty <TProperty>();
var existingChildren = await Set <T>().Where(x => x.Id == parent.Id).SelectMany(childSelector).AsNoTracking().ToListAsync();
if (comparer == null)
{
comparer = new BaseEntityComparer();
}
var addedChildren = currentChildren.Except(existingChildren, comparer).AsEnumerable();
var deletedChildren = existingChildren.Except(currentChildren, comparer).AsEnumerable();
foreach (var child in currentChildren)
{
await AddOrUpdate(child);
}
foreach (var child in addedChildren)
{
stateManager.ChangeRelationshipState(parent, child, childSelector.Name, EntityState.Added);
}
foreach (var child in deletedChildren)
{
Entry(child).State = EntityState.Unchanged;
stateManager.ChangeRelationshipState(parent, child, childSelector.Name, EntityState.Deleted);
}
}
public async Task UpdateForeignChildren <T, TProperty>(T parent, Expression <Func <T, IEnumerable <TProperty> > > childSelector, IEqualityComparer <TProperty> comparer = null) where T : BaseEntity where TProperty : BaseEntity
{
var children = (childSelector.Invoke(parent) ?? Enumerable.Empty <TProperty>()).ToList();
foreach (var child in children)
{
await AddOrUpdate(child);
}
var existingChildren = await Set <T>().Where(x => x.Id == parent.Id).SelectMany(childSelector).AsNoTracking().ToListAsync();
if (comparer == null)
{
comparer = new BaseEntityComparer();
}
foreach (var child in existingChildren.Except(children, comparer))
{
Entry(child).State = EntityState.Deleted;
}
}
