NSManagedObject的hasChanges为true，而changedValues为空 [英] NSManagedObject's hasChanges is true while changedValues is empty

问题描述

我正在尝试观察NSManagedObjectContextWillSaveNotification上各个NSManagedObject的变化:

I am trying to observe individual NSManagedObject changes on NSManagedObjectContextWillSaveNotification:

- (void)managedObjectContextWillSave:(NSNotification *)notification
{
    for (NSManagedObject * object in self.mutableObservedManagedObjects)
    {
        if (object.hasChanges)
        {
            [self managedObjectWasUpdated:object];
        }
    }
}

问题在于hasChanges为真而object.changedValues为空，因此错误地(?)触发了managedObjectWasUpdated:.

The problem is that hasChanges is true while object.changedValues is empty, thus wrongly (?) triggering managedObjectWasUpdated:.

我试图理解为什么会这样，如果我最好在致电managedObjectWasUpdated:之前检查object.changedValues.count.

I'm trying to understand why this is the case and if I should better check object.changedValues.count before calling managedObjectWasUpdated:.

isInserted和isDeleted均为假.

推荐答案

我遇到了相同的问题.而不是获取标志，我只是检查changedValues()是否为空.

I encountered the same issue. Instead of getting the flags, I just checked if changedValues() is empty.

对于Swift:

if !managedObject.changedValues().isEmpty {
    // Has some changed values
}

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