我同意这里可能存在漏洞。我已经修改了add对象setter的实现，以正确地追加到NSMutableOrderedSet。

- (void)addSubitemsObject:(SubItem *)value {
    NSMutableOrderedSet* tempSet = [NSMutableOrderedSet orderedSetWithOrderedSet:self.subitems];
    [tempSet addObject:value];
    self.subitems = tempSet;
}

将集合重新分配给self。子项将确保发送will /DidChangeValue通知。

我也遇到过同样的问题，但只是在我尝试了一些与我一直在做的不同的事情时。我无法看到subItem的代码，但我将假设它具有到item的反向链接。让我们称之为崇敬链接，“parentItem”，那么最简单的解决方案是:

Item *item = [NSEntityDescription insertNewObjectForEntityForName:@"Item" inManagedObjectContext:self.managedObjectContext];
item.name = @"FirstItem";

SubItem *subItem = [NSEntityDescription insertNewObjectForEntityForName:@"SubItem" inManagedObjectContext:self.managedObjectContext];

//[item addSubitemsObject:subItem];
subItem.parentItem = item;

结果是它使用了苹果自己的代码，而且简单干净。此外，集合被自动添加到，并且所有的观察者都被更新。没有问题。

我用您的数据模型和我自己的一个不同的名称复制了您的设置。两种情况下都有相同的错误。

看起来像是苹果自动生成代码中的bug。

我找到了一个对我有用的修复程序。我只是替换了这个:

[item addSubitemsObject:subItem];

用这个:

item.subitemsObject = subItem;

我已经找到窃听器了。它发生在willChangeValueForKey:withSetMutation:usingObjects:中。

这个呼叫会触发一连串的通知，可能很难追踪，当然，一个回复者的变化可能会影响到另一个，我怀疑这就是为什么苹果什么都没做的原因。

然而，这在Set中是可以的，只有OrderedSet上的Set操作会发生故障。这意味着只有四个方法需要修改。因此，我所做的只是将Set操作转换为等效的Array操作。这些工作非常完美，开销最小(但必要)。

On a critical level, this solution does suffer from one critical flaw; if you are adding objects and one of the objects already exists, then it is either not added or moved to the back of the ordered list (I don't know which). In either case, the expected ordered index of the object by the time we arrive at didChange is different from what was anticipated. This may break some people's apps, but it doesn't affect mine, since I am only ever adding new objects or I confirm their final locations before I add them.

- (void)addChildrenObject:(BAFinancialItem *)value {
    if ([self.children containsObject:value]) {
        return;
    }
    NSIndexSet * indexSet = [NSIndexSet indexSetWithIndex:self.children.count];
    [self willChange:NSKeyValueChangeInsertion valuesAtIndexes:indexSet forKey:ChildrenKey];
    [[self primitiveValueForKey:ChildrenKey] addObject:value];
    [self didChange:NSKeyValueChangeInsertion valuesAtIndexes:indexSet forKey:ChildrenKey];
}

- (void)removeChildrenObject:(BAFinancialItem *)value {
    if (![self.children containsObject:value]) {
        return;
    }
    NSIndexSet * indexSet = [NSIndexSet indexSetWithIndex:[self.children indexOfObject:value]];
    [self willChange:NSKeyValueChangeRemoval valuesAtIndexes:indexSet forKey:ChildrenKey];
    [[self primitiveValueForKey:ChildrenKey] removeObject:value];
    [self didChange:NSKeyValueChangeRemoval valuesAtIndexes:indexSet forKey:ChildrenKey];
}

- (void)addChildren:(NSOrderedSet *)values {
    if ([values isSubsetOfOrderedSet:self.children]) {
        return;
    }
    NSIndexSet * indexSet = [NSIndexSet indexSetWithIndexesInRange:NSMakeRange(self.children.count, values.count)];
    [self willChange:NSKeyValueChangeInsertion valuesAtIndexes:indexSet forKey:ChildrenKey];
    [[self primitiveValueForKey:ChildrenKey] unionOrderedSet:values];
    [self didChange:NSKeyValueChangeInsertion valuesAtIndexes:indexSet forKey:ChildrenKey];
}

- (void)removeChildren:(NSOrderedSet *)values {
    if (![self.children intersectsOrderedSet:values]) {
        return;
    }
    NSIndexSet * indexSet = [self.children indexesOfObjectsPassingTest:^BOOL(id obj, NSUInteger idx, BOOL *stop) {
        return [values containsObject:obj];
    }];
    [self willChange:NSKeyValueChangeRemoval valuesAtIndexes:indexSet forKey:ChildrenKey];
    [[self primitiveValueForKey:ChildrenKey] minusOrderedSet:values];
    [self didChange:NSKeyValueChangeRemoval valuesAtIndexes:indexSet forKey:ChildrenKey];
}

当然，还有一个更简单的解决方案。内容如下;

- (void)addChildrenObject:(BAFinancialItem *)value {
    if ([self.children containsObject:value]) {
        return;
    }
    [self insertObject:value inChildrenAtIndex:self.children.count];
}

- (void)removeChildrenObject:(BAFinancialItem *)value {
    if (![self.children containsObject:value]) {
        return;
    }
    [self removeObjectFromChildrenAtIndex:[self.children indexOfObject:value]];
}

- (void)addChildren:(NSOrderedSet *)values {
    if ([values isSubsetOfOrderedSet:self.children]) {
        return;
    }
    [self insertChildren:values atIndexes:[NSIndexSet indexSetWithIndexesInRange:NSMakeRange(self.children.count, values.count)]];
}

- (void)removeChildren:(NSOrderedSet *)values {
    if (![self.children intersectsOrderedSet:values]) {
        return;
    }
    [self removeChildrenAtIndexes:[self.children indexesOfObjectsPassingTest:^BOOL(id obj, NSUInteger idx, BOOL *stop) {
        return [values containsObject:obj];
    }]];
}

我也遇到了同样的情况，使用了一个名为“signals”的项目而不是“subitems”。使用tempset的解决方案在我的测试中是有效的。此外，我有一个问题与removeSignals:方法。这个重写似乎是有效的:

- (void)removeSignals:(NSOrderedSet *)values {
    NSMutableOrderedSet* tempset = [NSMutableOrderedSet orderedSetWithOrderedSet:self.signals];
    for (Signal* aSignal in values) {
        [tempset removeObject:aSignal];
    }
    self.signals = tempset;
}

如果有更好的方法，请告诉我。我的价值观输入从不超过10 -20项，所以性能不是一个太大的问题-尽管如此，请指出任何相关的东西。

谢谢,

达明