Question

我有一个继承自NSManagedObject的模型名为“Deletion”，代表一个coredata实体“Deletion”，所以在Deletion.m中我得到了以下方法：

- (NSString *)toJSON
{
    NSArray *keys         = [[NSArray alloc] initWithObjects:@"table", @"recordid", @"deleted", nil];
    NSMutableString *json = [NSMutableString stringWithString:@""];

    for(int i = 0; i < [keys count]; i++) {
        NSString *key = [keys objectAtIndex:i];
        id value      = [self valueForKeyPath:key];
        [json appendFormat:@"%@ \"%@\": \"%@\"", (i == 0 ? @"" : @", "), key, value];
        NSLog(@"deletion entry %@ has value %@", key, value);
    }
        NSLog(@"deleted has value %@", self.deleted);

    return [NSString stringWithFormat:@"{ %@ }", json];
}

这将在输出中打印以下内容：

2014-09-17 10:36:18.779 Heater (T)[905:60b] deletion entry table has value Piperun
2014-09-17 10:36:18.780 Heater (T)[905:60b] deletion entry recordid has value 256
2014-09-17 09:42:32.762 Heater (T)[876:60b] deletion entry deleted has value 0
2014-09-17 09:42:32.763 Heater (T)[876:60b] deleted has value 2014-09-17 07:42:29 +0000

为什么直接访问self.deleted有效，但现在通过valueForKeyPath？

[编辑：]我认为它与创建条目后保存模型有关。我在创建后调用[managedObjectContext save：＆amp; error]，没有别的，如果有帮助的话。

Answer 1

好的，我发现了问题。事实证明这是Core Data boolean key value change not reflected in fetch

的副本

问题在于：＆＃34;调用核心数据属性＆＃34;删除＆＃34;与NSManagedObject＆＃34;

的isDeleted属性冲突

模型valueForKeyPath不适用于日期？

1 个答案: